Add Plant Rooms/Zones feature for organizing plants by location

Implements Phase 3 of the feature roadmap:
- Room entity with 7 default rooms (Kitchen, Living Room, Bedroom, etc.)
- RoomRepositoryProtocol and CoreDataRoomRepository for persistence
- CreateDefaultRoomsUseCase and ManageRoomsUseCase for CRUD operations
- RoomsListView with swipe-to-delete and drag-to-reorder
- RoomEditorView with SF Symbol icon picker
- RoomPickerView for assigning plants to rooms
- Updated Plant entity (location → roomID) and PlantDetailView
- Added "Manage Rooms" section in SettingsView

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

PlantGuide/Core/DI/DIContainer.swift

@@ -205,6 +205,35 @@ final class DIContainer: DIContainerProtocol, ObservableObject {
         }
     }()
 
+    // MARK: - Room Services
+
+    private lazy var _coreDataRoomStorage: LazyService<CoreDataRoomRepository> = {
+        LazyService {
+            CoreDataRoomRepository(coreDataStack: CoreDataStack.shared)
+        }
+    }()
+
+    private lazy var _createDefaultRoomsUseCase: LazyService<CreateDefaultRoomsUseCase> = {
+        LazyService { [weak self] in
+            guard let self else {
+                fatalError("DIContainer deallocated unexpectedly")
+            }
+            return CreateDefaultRoomsUseCase(roomRepository: self.roomRepository)
+        }
+    }()
+
+    private lazy var _manageRoomsUseCase: LazyService<ManageRoomsUseCase> = {
+        LazyService { [weak self] in
+            guard let self else {
+                fatalError("DIContainer deallocated unexpectedly")
+            }
+            return ManageRoomsUseCase(
+                roomRepository: self.roomRepository,
+                plantRepository: self.plantCollectionRepository
+            )
+        }
+    }()
+
     // MARK: - Local Plant Database Services
 
     private lazy var _plantDatabaseService: LazyService<PlantDatabaseService> = {
@@ -270,6 +299,23 @@ final class DIContainer: DIContainerProtocol, ObservableObject {
         _coreDataPlantCareInfoStorage.value
     }
 
+    /// Room repository backed by Core Data
+    var roomRepository: RoomRepositoryProtocol {
+        _coreDataRoomStorage.value
+    }
+
+    // MARK: - Room Use Cases
+
+    /// Use case for creating default rooms on first app launch
+    var createDefaultRoomsUseCase: CreateDefaultRoomsUseCaseProtocol {
+        _createDefaultRoomsUseCase.value
+    }
+
+    /// Use case for managing rooms (CRUD operations)
+    var manageRoomsUseCase: ManageRoomsUseCaseProtocol {
+        _manageRoomsUseCase.value
+    }
+
     // MARK: - Initialization
 
     private init() {}
@@ -498,6 +544,11 @@ final class DIContainer: DIContainerProtocol, ObservableObject {
         BrowsePlantsViewModel(databaseService: plantDatabaseService)
     }
 
+    /// Factory method for RoomsViewModel
+    func makeRoomsViewModel() -> RoomsViewModel {
+        RoomsViewModel(manageRoomsUseCase: manageRoomsUseCase)
+    }
+
     // MARK: - Custom Registration
 
     /// Register a custom factory for a type
@@ -559,6 +610,10 @@ final class DIContainer: DIContainerProtocol, ObservableObject {
         // Identification use cases
         _identifyPlantOnDeviceUseCase.reset()
         _identifyPlantOnlineUseCase.reset()
+        // Room services
+        _coreDataRoomStorage.reset()
+        _createDefaultRoomsUseCase.reset()
+        _manageRoomsUseCase.reset()
         factories.removeAll()
         resolvedInstances.removeAll()
     }

PlantGuide/Data/DataSources/Local/CoreData/CoreDataPlantStorage.swift

@@ -97,7 +97,7 @@ final class CoreDataPlantStorage: PlantCollectionRepositoryProtocol, FavoritePla
             if let existingPlant = existingPlants.first {
                 // Update existing plant
                 existingPlant.updateFromPlant(plant)
-                Self.updateMutableFields(on: existingPlant, from: plant)
+                Self.updateMutableFields(on: existingPlant, from: plant, in: context)
             } else {
                 // Create new plant
                 guard let entity = NSEntityDescription.entity(forEntityName: plantEntityName, in: context) else {
@@ -106,7 +106,7 @@ final class CoreDataPlantStorage: PlantCollectionRepositoryProtocol, FavoritePla
 
                 let managedObject = NSManagedObject(entity: entity, insertInto: context)
                 managedObject.updateFromPlant(plant)
-                Self.updateMutableFields(on: managedObject, from: plant)
+                Self.updateMutableFields(on: managedObject, from: plant, in: context)
             }
 
             return ()
@@ -315,7 +315,7 @@ final class CoreDataPlantStorage: PlantCollectionRepositoryProtocol, FavoritePla
             }
 
             existingPlant.updateFromPlant(plant)
-            Self.updateMutableFields(on: existingPlant, from: plant)
+            Self.updateMutableFields(on: existingPlant, from: plant, in: context)
             return ()
         }
     }
@@ -442,14 +442,28 @@ final class CoreDataPlantStorage: PlantCollectionRepositoryProtocol, FavoritePla
     /// - Parameters:
     ///   - managedObject: The managed object to update
     ///   - plant: The plant domain entity with updated values
-    private static func updateMutableFields(on managedObject: NSManagedObject, from plant: Plant) {
+    ///   - context: The managed object context for fetching related objects
+    private static func updateMutableFields(on managedObject: NSManagedObject, from plant: Plant, in context: NSManagedObjectContext) {
         managedObject.setValue(plant.localImagePaths as NSArray, forKey: "localImagePaths")
         managedObject.setValue(plant.dateAdded, forKey: "dateAdded")
         managedObject.setValue(plant.confidenceScore, forKey: "confidenceScore")
         managedObject.setValue(plant.notes, forKey: "notes")
         managedObject.setValue(plant.isFavorite, forKey: "isFavorite")
         managedObject.setValue(plant.customName, forKey: "customName")
-        managedObject.setValue(plant.location, forKey: "location")
+
+        // Handle room relationship
+        if let roomID = plant.roomID {
+            // Fetch the RoomMO for the given roomID
+            let roomFetchRequest = RoomMO.fetchRequest()
+            roomFetchRequest.predicate = NSPredicate(format: "id == %@", roomID as CVarArg)
+            roomFetchRequest.fetchLimit = 1
+
+            if let roomMO = try? context.fetch(roomFetchRequest).first {
+                managedObject.setValue(roomMO, forKey: "room")
+            }
+        } else {
+            managedObject.setValue(nil, forKey: "room")
+        }
     }
 
     /// Converts a managed object to a Plant domain entity
@@ -479,7 +493,14 @@ final class CoreDataPlantStorage: PlantCollectionRepositoryProtocol, FavoritePla
         let notes = managedObject.value(forKey: "notes") as? String
         let isFavorite = (managedObject.value(forKey: "isFavorite") as? Bool) ?? false
         let customName = managedObject.value(forKey: "customName") as? String
-        let location = managedObject.value(forKey: "location") as? String
+
+        // Get roomID from the room relationship
+        let roomID: UUID?
+        if let roomMO = managedObject.value(forKey: "room") as? RoomMO {
+            roomID = roomMO.id
+        } else {
+            roomID = nil
+        }
 
         return Plant(
             id: id,
@@ -496,7 +517,7 @@ final class CoreDataPlantStorage: PlantCollectionRepositoryProtocol, FavoritePla
             notes: notes,
             isFavorite: isFavorite,
             customName: customName,
-            location: location
+            roomID: roomID
         )
     }
 

PlantGuide/Data/DataSources/Local/CoreData/CoreDataRoomRepository.swift

@@ -0,0 +1,231 @@
+//
+//  CoreDataRoomRepository.swift
+//  PlantGuide
+//
+//  Core Data implementation of room repository.
+//  Provides persistent storage for plant rooms/zones.
+//
+
+import CoreData
+import Foundation
+
+// MARK: - Core Data Room Repository
+
+/// Core Data-backed implementation of the room repository.
+/// Handles all persistent storage operations for plant rooms/zones.
+final class CoreDataRoomRepository: RoomRepositoryProtocol, @unchecked Sendable {
+
+    // MARK: - Properties
+
+    /// The Core Data stack used for persistence operations
+    private let coreDataStack: CoreDataStackProtocol
+
+    /// Entity name for room managed objects
+    private let roomEntityName = "RoomMO"
+
+    /// Entity name for plant managed objects
+    private let plantEntityName = "PlantMO"
+
+    /// The name of the "Other" room that cannot be deleted
+    private let otherRoomName = "Other"
+
+    // MARK: - Initialization
+
+    /// Creates a new Core Data room repository instance
+    /// - Parameter coreDataStack: The Core Data stack to use for persistence
+    init(coreDataStack: CoreDataStackProtocol = CoreDataStack.shared) {
+        self.coreDataStack = coreDataStack
+    }
+
+    // MARK: - RoomRepositoryProtocol
+
+    /// Fetches all rooms from Core Data, sorted by sortOrder
+    /// - Returns: An array of all stored rooms
+    /// - Throws: RoomStorageError if the fetch operation fails
+    func fetchAll() async throws -> [Room] {
+        try await coreDataStack.performBackgroundTask { context in
+            let fetchRequest = RoomMO.fetchRequest()
+            fetchRequest.sortDescriptors = [NSSortDescriptor(key: "sortOrder", ascending: true)]
+
+            let results = try context.fetch(fetchRequest)
+            return results.map { $0.toDomainModel() }
+        }
+    }
+
+    /// Fetches a room by its unique identifier
+    /// - Parameter id: The unique identifier of the room
+    /// - Returns: The room if found, or nil if no room exists with the given ID
+    /// - Throws: RoomStorageError if the fetch operation fails
+    func fetch(id: UUID) async throws -> Room? {
+        try await coreDataStack.performBackgroundTask { context in
+            let fetchRequest = RoomMO.fetchRequest()
+            fetchRequest.predicate = NSPredicate(format: "id == %@", id as CVarArg)
+            fetchRequest.fetchLimit = 1
+
+            let results = try context.fetch(fetchRequest)
+            return results.first?.toDomainModel()
+        }
+    }
+
+    /// Fetches the "Other" room, which is the default fallback room.
+    /// Creates default rooms if they don't exist.
+    /// - Returns: The "Other" room entity.
+    /// - Throws: An error if the fetch or creation operation fails.
+    func fetchOtherRoom() async throws -> Room {
+        // Ensure default rooms exist
+        try await createDefaultRoomsIfNeeded()
+
+        return try await coreDataStack.performBackgroundTask { [otherRoomName] context in
+            let fetchRequest = RoomMO.fetchRequest()
+            fetchRequest.predicate = NSPredicate(format: "name == %@", otherRoomName)
+            fetchRequest.fetchLimit = 1
+
+            let results = try context.fetch(fetchRequest)
+
+            guard let otherRoom = results.first else {
+                // This should never happen if createDefaultRoomsIfNeeded worked correctly
+                throw RoomStorageError.roomNotFound(UUID())
+            }
+
+            return otherRoom.toDomainModel()
+        }
+    }
+
+    /// Saves a new room to Core Data
+    /// - Parameter room: The room entity to save
+    /// - Throws: RoomStorageError if the save operation fails
+    func save(_ room: Room) async throws {
+        try await coreDataStack.performBackgroundTask { context in
+            // Check if room already exists
+            let fetchRequest = RoomMO.fetchRequest()
+            fetchRequest.predicate = NSPredicate(format: "id == %@", room.id as CVarArg)
+            fetchRequest.fetchLimit = 1
+
+            let existingRooms = try context.fetch(fetchRequest)
+
+            if let existingRoom = existingRooms.first {
+                // Update existing room
+                existingRoom.update(from: room)
+            } else {
+                // Create new room
+                _ = RoomMO.fromDomainModel(room, context: context)
+            }
+
+            return ()
+        }
+    }
+
+    /// Updates an existing room in Core Data
+    /// - Parameter room: The room with updated values to save
+    /// - Throws: RoomStorageError if the update operation fails or if the room is not found
+    func update(_ room: Room) async throws {
+        try await coreDataStack.performBackgroundTask { context in
+            let fetchRequest = RoomMO.fetchRequest()
+            fetchRequest.predicate = NSPredicate(format: "id == %@", room.id as CVarArg)
+            fetchRequest.fetchLimit = 1
+
+            let results = try context.fetch(fetchRequest)
+
+            guard let existingRoom = results.first else {
+                throw RoomStorageError.roomNotFound(room.id)
+            }
+
+            existingRoom.update(from: room)
+            return ()
+        }
+    }
+
+    /// Deletes a room by its unique identifier
+    /// The "Other" room cannot be deleted. When a room is deleted, plants
+    /// in that room will have their room reference set to nil (nullified).
+    /// - Parameter id: The unique identifier of the room to delete
+    /// - Throws: RoomStorageError if the delete operation fails or if attempting to delete the "Other" room
+    func delete(id: UUID) async throws {
+        try await coreDataStack.performBackgroundTask { [otherRoomName] context in
+            let fetchRequest = RoomMO.fetchRequest()
+            fetchRequest.predicate = NSPredicate(format: "id == %@", id as CVarArg)
+            fetchRequest.fetchLimit = 1
+
+            let results = try context.fetch(fetchRequest)
+
+            guard let roomToDelete = results.first else {
+                throw RoomStorageError.roomNotFound(id)
+            }
+
+            // Prevent deletion of the "Other" room specifically
+            if roomToDelete.name == otherRoomName {
+                throw RoomStorageError.cannotDeleteOtherRoom
+            }
+
+            // The relationship has Nullify deletion rule, so plants will have
+            // their room reference set to nil automatically
+            context.delete(roomToDelete)
+            return ()
+        }
+    }
+
+    /// Checks if a room exists with the given ID
+    /// - Parameter id: The unique identifier of the room
+    /// - Returns: True if the room exists, false otherwise
+    /// - Throws: RoomStorageError if the check operation fails
+    func exists(id: UUID) async throws -> Bool {
+        try await coreDataStack.performBackgroundTask { context in
+            let fetchRequest = RoomMO.fetchRequest()
+            fetchRequest.predicate = NSPredicate(format: "id == %@", id as CVarArg)
+            fetchRequest.fetchLimit = 1
+
+            let count = try context.count(for: fetchRequest)
+            return count > 0
+        }
+    }
+
+    /// Fetches the count of plants in a specific room.
+    /// - Parameter roomID: The unique identifier of the room.
+    /// - Returns: The number of plants in the room.
+    /// - Throws: An error if the count operation fails.
+    func plantCount(for roomID: UUID) async throws -> Int {
+        try await coreDataStack.performBackgroundTask { [plantEntityName] context in
+            let fetchRequest = NSFetchRequest<NSManagedObject>(entityName: plantEntityName)
+            fetchRequest.predicate = NSPredicate(format: "room.id == %@", roomID as CVarArg)
+
+            let count = try context.count(for: fetchRequest)
+            return count
+        }
+    }
+
+    /// Creates the default rooms if no rooms exist yet
+    /// - Throws: RoomStorageError if the creation operation fails
+    func createDefaultRoomsIfNeeded() async throws {
+        try await coreDataStack.performBackgroundTask { context in
+            // Check if any rooms exist
+            let fetchRequest = RoomMO.fetchRequest()
+            fetchRequest.fetchLimit = 1
+
+            let count = try context.count(for: fetchRequest)
+
+            guard count == 0 else {
+                // Rooms already exist, do nothing
+                return ()
+            }
+
+            // Create all default rooms
+            for room in Room.defaultRooms {
+                _ = RoomMO.fromDomainModel(room, context: context)
+            }
+
+            return ()
+        }
+    }
+}
+
+// MARK: - Testing Support
+
+#if DEBUG
+extension CoreDataRoomRepository {
+    /// Creates a repository instance with an in-memory Core Data stack for testing
+    /// - Returns: A CoreDataRoomRepository instance backed by an in-memory store
+    static func inMemoryRepository() -> CoreDataRoomRepository {
+        return CoreDataRoomRepository(coreDataStack: CoreDataStack.inMemoryStack())
+    }
+}
+#endif

PlantGuide/Data/DataSources/Local/CoreData/ManagedObjects/PlantMO.swift

@@ -68,6 +68,9 @@ public class PlantMO: NSManagedObject {
 
     /// Cached care information from Trefle API (optional, one-to-one, cascade delete)
     @NSManaged public var plantCareInfo: PlantCareInfoMO?
+
+    /// The room where this plant is located (optional, to-one)
+    @NSManaged public var room: RoomMO?
 }
 
 // MARK: - Domain Model Conversion
@@ -94,7 +97,7 @@ extension PlantMO {
             notes: notes,
             isFavorite: isFavorite,
             customName: customName,
-            location: location
+            roomID: room?.id
         )
     }
 
@@ -120,13 +123,16 @@ extension PlantMO {
         plantMO.notes = plant.notes
         plantMO.isFavorite = plant.isFavorite
         plantMO.customName = plant.customName
-        plantMO.location = plant.location
+        // Note: roomID is stored via the room relationship
+        // The room relationship should be set separately when saving
+        // plantMO.room is set by the repository based on roomID
 
         return plantMO
     }
 
     /// Updates this managed object with values from a Plant domain model.
     /// - Parameter plant: The Plant domain entity to update from.
+    /// - Note: The room relationship should be set separately via setRoom(id:context:).
     func update(from plant: Plant) {
         id = plant.id
         scientificName = plant.scientificName
@@ -142,7 +148,28 @@ extension PlantMO {
         notes = plant.notes
         isFavorite = plant.isFavorite
         customName = plant.customName
-        location = plant.location
+        // Note: roomID is stored via the room relationship
+        // The room relationship should be set separately when saving
+        // The room relationship is set by the repository based on roomID
+    }
+
+    /// Sets the room relationship by looking up the room by ID.
+    /// - Parameters:
+    ///   - roomID: The ID of the room to associate, or nil to clear the room.
+    ///   - context: The managed object context to use for the lookup.
+    func setRoom(id roomID: UUID?, context: NSManagedObjectContext) {
+        guard let roomID = roomID else {
+            room = nil
+            return
+        }
+
+        let fetchRequest = RoomMO.fetchRequest()
+        fetchRequest.predicate = NSPredicate(format: "id == %@", roomID as CVarArg)
+        fetchRequest.fetchLimit = 1
+
+        if let roomMO = try? context.fetch(fetchRequest).first {
+            room = roomMO
+        }
     }
 }
 

PlantGuide/Data/DataSources/Local/CoreData/ManagedObjects/RoomMO.swift

@@ -0,0 +1,112 @@
+//
+//  RoomMO.swift
+//  PlantGuide
+//
+//  Core Data managed object representing a Room entity.
+//  Maps to the Room domain model for persistence.
+//
+
+import CoreData
+import Foundation
+
+// MARK: - RoomMO
+
+/// Core Data managed object representing a Room entity.
+/// Maps to the Room domain model for persistence.
+@objc(RoomMO)
+public class RoomMO: NSManagedObject {
+
+    // MARK: - Properties
+
+    /// Unique identifier for the room
+    @NSManaged public var id: UUID
+
+    /// The display name of the room (e.g., "Kitchen", "Living Room")
+    @NSManaged public var name: String
+
+    /// SF Symbol name for the room's icon (e.g., "refrigerator", "sofa")
+    @NSManaged public var icon: String
+
+    /// Position in the sorted list of rooms (lower values appear first)
+    @NSManaged public var sortOrder: Int32
+
+    /// System-created rooms cannot be deleted by the user
+    @NSManaged public var isDefault: Bool
+
+    // MARK: - Relationships
+
+    /// The plants located in this room (one-to-many)
+    @NSManaged public var plants: NSSet?
+}
+
+// MARK: - Generated Accessors for Plants
+
+extension RoomMO {
+
+    @objc(addPlantsObject:)
+    @NSManaged public func addToPlants(_ value: PlantMO)
+
+    @objc(removePlantsObject:)
+    @NSManaged public func removeFromPlants(_ value: PlantMO)
+
+    @objc(addPlants:)
+    @NSManaged public func addToPlants(_ values: NSSet)
+
+    @objc(removePlants:)
+    @NSManaged public func removeFromPlants(_ values: NSSet)
+}
+
+// MARK: - Domain Model Conversion
+
+extension RoomMO {
+
+    /// Converts this managed object to a Room domain model.
+    /// - Returns: A Room domain entity populated with this managed object's data.
+    func toDomainModel() -> Room {
+        return Room(
+            id: id,
+            name: name,
+            icon: icon,
+            sortOrder: Int(sortOrder),
+            isDefault: isDefault
+        )
+    }
+
+    /// Creates a RoomMO managed object from a Room domain model.
+    /// - Parameters:
+    ///   - room: The Room domain entity to convert.
+    ///   - context: The managed object context to create the object in.
+    /// - Returns: A new RoomMO instance populated with the room's data.
+    static func fromDomainModel(_ room: Room, context: NSManagedObjectContext) -> RoomMO {
+        let roomMO = RoomMO(context: context)
+
+        roomMO.id = room.id
+        roomMO.name = room.name
+        roomMO.icon = room.icon
+        roomMO.sortOrder = Int32(room.sortOrder)
+        roomMO.isDefault = room.isDefault
+
+        return roomMO
+    }
+
+    /// Updates this managed object with values from a Room domain model.
+    /// - Parameter room: The Room domain entity to update from.
+    func update(from room: Room) {
+        id = room.id
+        name = room.name
+        icon = room.icon
+        sortOrder = Int32(room.sortOrder)
+        isDefault = room.isDefault
+    }
+}
+
+// MARK: - Fetch Request
+
+extension RoomMO {
+
+    /// Creates a fetch request for RoomMO entities.
+    /// - Returns: A configured NSFetchRequest for RoomMO.
+    @nonobjc public class func fetchRequest() -> NSFetchRequest<RoomMO> {
+        return NSFetchRequest<RoomMO>(entityName: "RoomMO")
+    }
+}

PlantGuide/Data/DataSources/Local/CoreData/PlantGuideModel.xcdatamodeld/PlantGuideModel.xcdatamodel/contents

@@ -19,6 +19,7 @@
         <relationship name="careSchedule" optional="YES" maxCount="1" deletionRule="Cascade" destinationEntity="CareScheduleMO" inverseName="plant" inverseEntity="CareScheduleMO"/>
         <relationship name="identifications" optional="YES" toMany="YES" deletionRule="Cascade" destinationEntity="IdentificationMO" inverseName="plant" inverseEntity="IdentificationMO"/>
         <relationship name="plantCareInfo" optional="YES" maxCount="1" deletionRule="Cascade" destinationEntity="PlantCareInfoMO" inverseName="plant" inverseEntity="PlantCareInfoMO"/>
+        <relationship name="room" optional="YES" maxCount="1" deletionRule="Nullify" destinationEntity="RoomMO" inverseName="plants" inverseEntity="RoomMO"/>
     </entity>
     <entity name="IdentificationMO" representedClassName="IdentificationMO" syncable="YES">
         <attribute name="confidenceScore" attributeType="Double" defaultValueString="0.0" usesScalarType="YES"/>
@@ -67,4 +68,12 @@
         <attribute name="wateringScheduleData" attributeType="Binary"/>
         <relationship name="plant" optional="YES" maxCount="1" deletionRule="Nullify" destinationEntity="PlantMO" inverseName="plantCareInfo" inverseEntity="PlantMO"/>
     </entity>
+    <entity name="RoomMO" representedClassName="RoomMO" syncable="YES">
+        <attribute name="icon" attributeType="String"/>
+        <attribute name="id" attributeType="UUID" usesScalarType="NO"/>
+        <attribute name="isDefault" attributeType="Boolean" defaultValueString="NO" usesScalarType="YES"/>
+        <attribute name="name" attributeType="String"/>
+        <attribute name="sortOrder" attributeType="Integer 32" defaultValueString="0" usesScalarType="YES"/>
+        <relationship name="plants" optional="YES" toMany="YES" deletionRule="Nullify" destinationEntity="PlantMO" inverseName="room" inverseEntity="PlantMO"/>
+    </entity>
 </model>

PlantGuide/Data/Mappers/PredictionToPlantMapper.swift

@@ -65,7 +65,7 @@ struct PredictionToPlantMapper {
             notes: nil,
             isFavorite: false,
             customName: nil,
-            location: nil
+            roomID: nil
         )
     }
 

PlantGuide/Data/Mappers/RoomMapper.swift

@@ -0,0 +1,101 @@
+//
+//  RoomMapper.swift
+//  PlantGuide
+//
+//  Mapper for converting between Room domain entities and RoomMO managed objects.
+//
+
+import CoreData
+import Foundation
+
+// MARK: - RoomMapper
+
+/// Maps between Room domain entities and RoomMO Core Data managed objects.
+///
+/// This mapper provides conversion functions for transforming between the
+/// Room domain model used in the business logic layer and the RoomMO
+/// managed object used for Core Data persistence.
+struct RoomMapper {
+
+    // MARK: - Domain to Managed Object
+
+    /// Creates a new RoomMO managed object from a Room domain entity.
+    ///
+    /// This function creates a new managed object in the provided context
+    /// and populates it with data from the domain entity.
+    ///
+    /// - Parameters:
+    ///   - room: The Room domain entity to convert.
+    ///   - context: The managed object context to create the object in.
+    /// - Returns: A new RoomMO instance populated with the room's data.
+    static func toManagedObject(_ room: Room, in context: NSManagedObjectContext) -> RoomMO {
+        let roomMO = RoomMO(context: context)
+        populate(roomMO, from: room)
+        return roomMO
+    }
+
+    /// Populates a RoomMO managed object with data from a Room domain entity.
+    ///
+    /// Use this function to update an existing managed object with new values
+    /// from a domain entity.
+    ///
+    /// - Parameters:
+    ///   - roomMO: The managed object to populate.
+    ///   - room: The Room domain entity to get data from.
+    static func populate(_ roomMO: RoomMO, from room: Room) {
+        roomMO.id = room.id
+        roomMO.name = room.name
+        roomMO.icon = room.icon
+        roomMO.sortOrder = Int32(room.sortOrder)
+        roomMO.isDefault = room.isDefault
+    }
+
+    // MARK: - Managed Object to Domain
+
+    /// Converts a RoomMO managed object to a Room domain entity.
+    ///
+    /// - Parameter roomMO: The managed object to convert.
+    /// - Returns: A Room domain entity populated with the managed object's data.
+    static func toDomainModel(_ roomMO: RoomMO) -> Room {
+        return Room(
+            id: roomMO.id,
+            name: roomMO.name,
+            icon: roomMO.icon,
+            sortOrder: Int(roomMO.sortOrder),
+            isDefault: roomMO.isDefault
+        )
+    }
+
+    /// Converts an array of RoomMO managed objects to Room domain entities.
+    ///
+    /// - Parameter roomMOs: The managed objects to convert.
+    /// - Returns: An array of Room domain entities.
+    static func toDomainModels(_ roomMOs: [RoomMO]) -> [Room] {
+        return roomMOs.map { toDomainModel($0) }
+    }
+
+    // MARK: - Batch Operations
+
+    /// Creates multiple RoomMO managed objects from an array of Room domain entities.
+    ///
+    /// - Parameters:
+    ///   - rooms: The Room domain entities to convert.
+    ///   - context: The managed object context to create the objects in.
+    /// - Returns: An array of RoomMO instances populated with the rooms' data.
+    static func toManagedObjects(_ rooms: [Room], in context: NSManagedObjectContext) -> [RoomMO] {
+        return rooms.map { toManagedObject($0, in: context) }
+    }
+
+    // MARK: - Default Rooms
+
+    /// Creates RoomMO managed objects for all default rooms.
+    ///
+    /// This function creates managed objects for the predefined default rooms
+    /// (Kitchen, Living Room, Bedroom, Bathroom, Office, Patio/Balcony, Other).
+    ///
+    /// - Parameter context: The managed object context to create the objects in.
+    /// - Returns: An array of RoomMO instances for all default rooms.
+    static func createDefaultRooms(in context: NSManagedObjectContext) -> [RoomMO] {
+        return toManagedObjects(Room.defaultRooms, in: context)
+    }
+}

PlantGuide/Domain/Entities/Plant.swift

@@ -56,8 +56,8 @@ struct Plant: Identifiable, Sendable, Equatable, Hashable {
     /// A custom name the user has given to this plant
     var customName: String?
 
-    /// Description of where the plant is located (e.g., "Living room window", "Backyard garden")
+    /// The ID of the room where the plant is located (e.g., Kitchen, Living Room)
-    var location: String?
+    var roomID: UUID?
 
     // MARK: - Computed Properties
 
@@ -85,7 +85,7 @@ struct Plant: Identifiable, Sendable, Equatable, Hashable {
     ///   - notes: User notes about the plant. Defaults to nil.
     ///   - isFavorite: Whether marked as favorite. Defaults to false.
     ///   - customName: User's custom name for the plant. Defaults to nil.
-    ///   - location: Where the plant is located. Defaults to nil.
+    ///   - roomID: The ID of the room where the plant is located. Defaults to nil.
     init(
         id: UUID = UUID(),
         scientificName: String,
@@ -101,7 +101,7 @@ struct Plant: Identifiable, Sendable, Equatable, Hashable {
         notes: String? = nil,
         isFavorite: Bool = false,
         customName: String? = nil,
-        location: String? = nil
+        roomID: UUID? = nil
     ) {
         self.id = id
         self.scientificName = scientificName
@@ -117,7 +117,7 @@ struct Plant: Identifiable, Sendable, Equatable, Hashable {
         self.notes = notes
         self.isFavorite = isFavorite
         self.customName = customName
-        self.location = location
+        self.roomID = roomID
     }
 
     // MARK: - Hashable

PlantGuide/Domain/Entities/Room.swift

@@ -0,0 +1,87 @@
+//
+//  Room.swift
+//  PlantGuide
+//
+//  Created for PlantGuide plant identification app.
+//
+
+import Foundation
+
+// MARK: - Room
+
+/// Represents a room/zone where plants can be located.
+///
+/// Rooms provide organizational grouping for plants, allowing users to
+/// track which plants are in which areas of their home or garden.
+/// Default rooms are provided on first launch and cannot be deleted,
+/// while custom rooms can be freely created, edited, and removed.
+///
+/// Conforms to Hashable for efficient use in SwiftUI ForEach and NavigationLink.
+/// The hash is based only on the immutable `id` property for stable identity,
+/// while Equatable compares all properties for change detection.
+struct Room: Identifiable, Sendable, Equatable, Hashable, Codable {
+
+    // MARK: - Properties
+
+    /// Unique identifier for the room
+    let id: UUID
+
+    /// The display name of the room (e.g., "Kitchen", "Living Room")
+    var name: String
+
+    /// SF Symbol name for the room's icon (e.g., "refrigerator", "sofa")
+    var icon: String
+
+    /// Position in the sorted list of rooms (lower values appear first)
+    var sortOrder: Int
+
+    /// System-created rooms cannot be deleted by the user
+    let isDefault: Bool
+
+    // MARK: - Initialization
+
+    /// Creates a new Room instance.
+    ///
+    /// - Parameters:
+    ///   - id: Unique identifier for the room. Defaults to a new UUID.
+    ///   - name: The display name of the room.
+    ///   - icon: SF Symbol name for the room's icon.
+    ///   - sortOrder: Position in the sorted list of rooms.
+    ///   - isDefault: Whether this is a system-created default room. Defaults to false.
+    init(
+        id: UUID = UUID(),
+        name: String,
+        icon: String,
+        sortOrder: Int,
+        isDefault: Bool = false
+    ) {
+        self.id = id
+        self.name = name
+        self.icon = icon
+        self.sortOrder = sortOrder
+        self.isDefault = isDefault
+    }
+
+    // MARK: - Hashable
+
+    /// Custom hash implementation using only the id for stable identity.
+    /// This ensures consistent behavior in SwiftUI collections and navigation,
+    /// where identity should remain stable even when mutable properties change.
+    func hash(into hasher: inout Hasher) {
+        hasher.combine(id)
+    }
+
+    // MARK: - Default Rooms
+
+    /// The set of default rooms created on first app launch.
+    /// These rooms cover common household locations and cannot be deleted.
+    static let defaultRooms: [Room] = [
+        Room(name: "Kitchen", icon: "refrigerator", sortOrder: 0, isDefault: true),
+        Room(name: "Living Room", icon: "sofa", sortOrder: 1, isDefault: true),
+        Room(name: "Bedroom", icon: "bed.double", sortOrder: 2, isDefault: true),
+        Room(name: "Bathroom", icon: "shower", sortOrder: 3, isDefault: true),
+        Room(name: "Office", icon: "desktopcomputer", sortOrder: 4, isDefault: true),
+        Room(name: "Patio/Balcony", icon: "sun.max", sortOrder: 5, isDefault: true),
+        Room(name: "Other", icon: "square.grid.2x2", sortOrder: 6, isDefault: true),
+    ]
+}

PlantGuide/Domain/RepositoryInterfaces/RoomRepositoryProtocol.swift

@@ -0,0 +1,143 @@
+//
+//  RoomRepositoryProtocol.swift
+//  PlantGuide
+//
+//  Repository protocol defining the data access contract for Room entities.
+//  Implementations handle persistence operations for room/zone data.
+//
+
+import Foundation
+
+// MARK: - Room Storage Error
+
+/// Errors that can occur during room storage operations
+enum RoomStorageError: Error, LocalizedError {
+    /// The room with the specified ID was not found
+    case roomNotFound(UUID)
+    /// Failed to save room data
+    case saveFailed(Error)
+    /// Failed to fetch room data
+    case fetchFailed(Error)
+    /// Failed to delete room data
+    case deleteFailed(Error)
+    /// Failed to update room data
+    case updateFailed(Error)
+    /// Attempted to delete the "Other" room which cannot be deleted
+    case cannotDeleteOtherRoom
+    /// Attempted to delete a default room
+    case cannotDeleteDefaultRoom(String)
+    /// The Core Data entity was not found in the model
+    case entityNotFound(String)
+
+    var errorDescription: String? {
+        switch self {
+        case .roomNotFound(let id):
+            return "Room with ID \(id) was not found"
+        case .saveFailed(let error):
+            return "Failed to save room: \(error.localizedDescription)"
+        case .fetchFailed(let error):
+            return "Failed to fetch room data: \(error.localizedDescription)"
+        case .deleteFailed(let error):
+            return "Failed to delete room: \(error.localizedDescription)"
+        case .updateFailed(let error):
+            return "Failed to update room: \(error.localizedDescription)"
+        case .cannotDeleteOtherRoom:
+            return "The 'Other' room cannot be deleted"
+        case .cannotDeleteDefaultRoom(let name):
+            return "The default room '\(name)' cannot be deleted"
+        case .entityNotFound(let name):
+            return "Entity '\(name)' not found in Core Data model"
+        }
+    }
+}
+
+// MARK: - RoomRepositoryProtocol
+
+/// Repository protocol defining the data access contract for Room entities.
+/// Implementations handle persistence operations for room/zone data.
+///
+/// Rooms provide organizational grouping for plants in the user's collection.
+/// The repository manages both default system rooms and user-created custom rooms.
+protocol RoomRepositoryProtocol: Sendable {
+
+    // MARK: - Fetch Operations
+
+    /// Fetches all rooms from the repository, sorted by sortOrder.
+    ///
+    /// - Returns: An array of all stored rooms, sorted by their sortOrder property.
+    /// - Throws: An error if the fetch operation fails.
+    func fetchAll() async throws -> [Room]
+
+    /// Fetches a room by its unique identifier.
+    ///
+    /// - Parameter id: The unique identifier of the room to fetch.
+    /// - Returns: The room if found, or nil if no room exists with the given ID.
+    /// - Throws: An error if the fetch operation fails.
+    func fetch(id: UUID) async throws -> Room?
+
+    /// Fetches the "Other" room, which is the default fallback room.
+    /// Creates default rooms if they don't exist.
+    ///
+    /// - Returns: The "Other" room entity.
+    /// - Throws: An error if the fetch or creation operation fails.
+    func fetchOtherRoom() async throws -> Room
+
+    // MARK: - Save Operations
+
+    /// Saves a new room to the repository.
+    ///
+    /// Use this method to persist a newly created room. For updating existing
+    /// rooms, use the `update(_:)` method instead.
+    ///
+    /// - Parameter room: The room entity to save.
+    /// - Throws: An error if the save operation fails.
+    func save(_ room: Room) async throws
+
+    /// Updates an existing room in the repository.
+    ///
+    /// Use this method to persist changes to a room's mutable properties
+    /// (name, icon, sortOrder). The room must already exist in the repository.
+    ///
+    /// - Parameter room: The room with updated values to save.
+    /// - Throws: An error if the update operation fails or if the room is not found.
+    func update(_ room: Room) async throws
+
+    // MARK: - Delete Operations
+
+    /// Deletes a room by its unique identifier.
+    ///
+    /// The "Other" room cannot be deleted. When a room is deleted, plants
+    /// in that room will have their room reference set to nil (nullified).
+    ///
+    /// - Parameter id: The unique identifier of the room to delete.
+    /// - Throws: `RoomStorageError.cannotDeleteOtherRoom` if attempting to delete the "Other" room.
+    ///           `RoomStorageError.roomNotFound` if the room doesn't exist.
+    func delete(id: UUID) async throws
+
+    // MARK: - Query Operations
+
+    /// Checks if a room exists with the given identifier.
+    ///
+    /// - Parameter id: The unique identifier of the room to check.
+    /// - Returns: True if the room exists, false otherwise.
+    /// - Throws: An error if the check operation fails.
+    func exists(id: UUID) async throws -> Bool
+
+    /// Fetches the count of plants in a specific room.
+    ///
+    /// - Parameter roomID: The unique identifier of the room.
+    /// - Returns: The number of plants in the room.
+    /// - Throws: An error if the count operation fails.
+    func plantCount(for roomID: UUID) async throws -> Int
+
+    // MARK: - Initialization
+
+    /// Creates the default rooms if no rooms exist yet.
+    ///
+    /// This method should be called on first app launch to populate
+    /// the room list with the predefined default rooms from `Room.defaultRooms`.
+    /// If any rooms already exist, this method should do nothing.
+    ///
+    /// - Throws: An error if the creation operation fails.
+    func createDefaultRoomsIfNeeded() async throws
+}

PlantGuide/Domain/UseCases/Room/CreateDefaultRoomsUseCase.swift

@@ -0,0 +1,139 @@
+//
+//  CreateDefaultRoomsUseCase.swift
+//  PlantGuide
+//
+//  Created for PlantGuide plant identification app.
+//
+
+import Foundation
+
+// MARK: - CreateDefaultRoomsUseCaseProtocol
+
+/// Protocol defining the interface for creating default rooms on first app launch.
+///
+/// This protocol enables dependency injection and easy mocking for unit tests.
+/// The use case ensures that users have a set of predefined rooms to choose from
+/// when organizing their plant collection.
+protocol CreateDefaultRoomsUseCaseProtocol: Sendable {
+    /// Creates the default rooms if no rooms exist yet.
+    ///
+    /// This method should be called during app initialization (e.g., on first launch)
+    /// to populate the room list with predefined rooms like "Kitchen", "Living Room", etc.
+    /// If any rooms already exist in the repository, this method does nothing.
+    ///
+    /// - Throws: `CreateDefaultRoomsError` if the creation fails.
+    ///
+    /// Example usage:
+    /// ```swift
+    /// // In AppDelegate or app initialization
+    /// try await createDefaultRoomsUseCase.execute()
+    /// ```
+    func execute() async throws
+}
+
+// MARK: - CreateDefaultRoomsError
+
+/// Errors that can occur when creating default rooms.
+///
+/// These errors provide specific context for creation failures,
+/// enabling appropriate error handling and logging.
+enum CreateDefaultRoomsError: Error, LocalizedError {
+    /// Failed to check if rooms already exist.
+    case checkExistingFailed(Error)
+
+    /// Failed to save one or more default rooms.
+    case saveFailed(Error)
+
+    // MARK: - LocalizedError
+
+    var errorDescription: String? {
+        switch self {
+        case .checkExistingFailed(let error):
+            return "Failed to check existing rooms: \(error.localizedDescription)"
+        case .saveFailed(let error):
+            return "Failed to create default rooms: \(error.localizedDescription)"
+        }
+    }
+
+    var failureReason: String? {
+        switch self {
+        case .checkExistingFailed:
+            return "Could not determine if default rooms already exist."
+        case .saveFailed:
+            return "The default room data could not be persisted to storage."
+        }
+    }
+
+    var recoverySuggestion: String? {
+        switch self {
+        case .checkExistingFailed, .saveFailed:
+            return "Please restart the app. If the problem persists, reinstall the app."
+        }
+    }
+}
+
+// MARK: - CreateDefaultRoomsUseCase
+
+/// Use case for creating default rooms on first app launch.
+///
+/// This use case handles the initialization of the room list with predefined
+/// rooms that cover common household locations. It's designed to be idempotent,
+/// meaning it can be called multiple times safely without creating duplicates.
+///
+/// ## Default Rooms Created
+/// - Kitchen
+/// - Living Room
+/// - Bedroom
+/// - Bathroom
+/// - Office
+/// - Patio/Balcony
+/// - Other
+///
+/// ## Example Usage
+/// ```swift
+/// let useCase = CreateDefaultRoomsUseCase(roomRepository: roomRepository)
+///
+/// // Call during app initialization
+/// try await useCase.execute()
+/// ```
+final class CreateDefaultRoomsUseCase: CreateDefaultRoomsUseCaseProtocol, @unchecked Sendable {
+
+    // MARK: - Dependencies
+
+    private let roomRepository: RoomRepositoryProtocol
+
+    // MARK: - Initialization
+
+    /// Creates a new CreateDefaultRoomsUseCase instance.
+    ///
+    /// - Parameter roomRepository: Repository for persisting room entities.
+    init(roomRepository: RoomRepositoryProtocol) {
+        self.roomRepository = roomRepository
+    }
+
+    // MARK: - CreateDefaultRoomsUseCaseProtocol
+
+    func execute() async throws {
+        // Check if any rooms already exist
+        let existingRooms: [Room]
+        do {
+            existingRooms = try await roomRepository.fetchAll()
+        } catch {
+            throw CreateDefaultRoomsError.checkExistingFailed(error)
+        }
+
+        // If rooms already exist, do nothing
+        guard existingRooms.isEmpty else {
+            return
+        }
+
+        // Create all default rooms
+        do {
+            for room in Room.defaultRooms {
+                try await roomRepository.save(room)
+            }
+        } catch {
+            throw CreateDefaultRoomsError.saveFailed(error)
+        }
+    }
+}

PlantGuide/Domain/UseCases/Room/ManageRoomsUseCase.swift

@@ -0,0 +1,374 @@
+//
+//  ManageRoomsUseCase.swift
+//  PlantGuide
+//
+//  Created for PlantGuide plant identification app.
+//
+
+import Foundation
+
+// MARK: - ManageRoomsUseCaseProtocol
+
+/// Protocol defining the interface for managing rooms in the user's collection.
+///
+/// This protocol enables dependency injection and easy mocking for unit tests.
+/// Implementations coordinate CRUD operations on rooms, including the ability
+/// to reassign plants when a room is deleted.
+protocol ManageRoomsUseCaseProtocol: Sendable {
+
+    /// Creates a new custom room with the specified name and icon.
+    ///
+    /// The room is automatically assigned a sortOrder that places it at the end
+    /// of the room list, after all existing rooms.
+    ///
+    /// - Parameters:
+    ///   - name: The display name for the new room.
+    ///   - icon: The SF Symbol name for the room's icon.
+    /// - Returns: The newly created and saved room.
+    /// - Throws: `ManageRoomsError` if the creation fails.
+    ///
+    /// Example usage:
+    /// ```swift
+    /// let newRoom = try await useCase.createRoom(name: "Sunroom", icon: "sun.max.fill")
+    /// ```
+    func createRoom(name: String, icon: String) async throws -> Room
+
+    /// Updates an existing room's properties.
+    ///
+    /// Only mutable properties (name, icon, sortOrder) can be updated.
+    /// The room's id and isDefault status cannot be changed.
+    ///
+    /// - Parameter room: The room with updated values to save.
+    /// - Throws: `ManageRoomsError` if the update fails.
+    ///
+    /// Example usage:
+    /// ```swift
+    /// var room = existingRoom
+    /// room.name = "Guest Bedroom"
+    /// room.icon = "bed.double.fill"
+    /// try await useCase.updateRoom(room)
+    /// ```
+    func updateRoom(_ room: Room) async throws
+
+    /// Deletes a room and optionally reassigns its plants to another room.
+    ///
+    /// Default rooms (where `isDefault == true`) cannot be deleted and will
+    /// throw a `cannotDeleteDefaultRoom` error.
+    ///
+    /// - Parameters:
+    ///   - id: The unique identifier of the room to delete.
+    ///   - reassignPlantsTo: Optional ID of another room to move plants to.
+    ///                       If nil, plants in the deleted room will have their
+    ///                       room assignment cleared.
+    /// - Throws: `ManageRoomsError` if the deletion fails or if attempting
+    ///           to delete a default room.
+    ///
+    /// Example usage:
+    /// ```swift
+    /// // Delete room and reassign plants to another room
+    /// try await useCase.deleteRoom(id: roomToDelete.id, reassignPlantsTo: otherRoom.id)
+    ///
+    /// // Delete room and clear plant assignments
+    /// try await useCase.deleteRoom(id: roomToDelete.id, reassignPlantsTo: nil)
+    /// ```
+    func deleteRoom(id: UUID, reassignPlantsTo: UUID?) async throws
+
+    /// Retrieves all rooms, sorted by sortOrder.
+    ///
+    /// - Returns: An array of all rooms, sorted by their sortOrder property.
+    /// - Throws: `ManageRoomsError` if the fetch fails.
+    ///
+    /// Example usage:
+    /// ```swift
+    /// let rooms = try await useCase.getAllRooms()
+    /// for room in rooms {
+    ///     print("\(room.name): \(room.icon)")
+    /// }
+    /// ```
+    func getAllRooms() async throws -> [Room]
+
+    /// Updates the sort order of multiple rooms at once.
+    ///
+    /// Use this method after the user reorders rooms via drag-and-drop.
+    /// The sortOrder of each room in the array is updated to match its
+    /// position in the array (index 0 = sortOrder 0, etc.).
+    ///
+    /// - Parameter rooms: The rooms in their new sorted order.
+    /// - Throws: `ManageRoomsError` if the update fails.
+    ///
+    /// Example usage:
+    /// ```swift
+    /// // After user drag-and-drop reordering
+    /// let reorderedRooms = [room3, room1, room2]
+    /// try await useCase.reorderRooms(reorderedRooms)
+    /// ```
+    func reorderRooms(_ rooms: [Room]) async throws
+}
+
+// MARK: - ManageRoomsError
+
+/// Errors that can occur when managing rooms.
+///
+/// These errors provide specific context for room operation failures,
+/// enabling appropriate error handling and user messaging.
+enum ManageRoomsError: Error, LocalizedError {
+    /// The room with the specified ID was not found.
+    case roomNotFound(roomID: UUID)
+
+    /// Cannot delete a default (system-created) room.
+    case cannotDeleteDefaultRoom(roomID: UUID)
+
+    /// The target room for plant reassignment was not found.
+    case reassignmentTargetNotFound(roomID: UUID)
+
+    /// Failed to save the room to the repository.
+    case saveFailed(Error)
+
+    /// Failed to update the room in the repository.
+    case updateFailed(Error)
+
+    /// Failed to delete the room from the repository.
+    case deleteFailed(Error)
+
+    /// Failed to fetch rooms from the repository.
+    case fetchFailed(Error)
+
+    /// Failed to reassign plants to another room.
+    case plantReassignmentFailed(Error)
+
+    // MARK: - LocalizedError
+
+    var errorDescription: String? {
+        switch self {
+        case .roomNotFound(let roomID):
+            return "Room not found: \(roomID)"
+        case .cannotDeleteDefaultRoom:
+            return "Cannot delete a default room."
+        case .reassignmentTargetNotFound(let roomID):
+            return "Target room for reassignment not found: \(roomID)"
+        case .saveFailed(let error):
+            return "Failed to create room: \(error.localizedDescription)"
+        case .updateFailed(let error):
+            return "Failed to update room: \(error.localizedDescription)"
+        case .deleteFailed(let error):
+            return "Failed to delete room: \(error.localizedDescription)"
+        case .fetchFailed(let error):
+            return "Failed to load rooms: \(error.localizedDescription)"
+        case .plantReassignmentFailed(let error):
+            return "Failed to reassign plants: \(error.localizedDescription)"
+        }
+    }
+
+    var failureReason: String? {
+        switch self {
+        case .roomNotFound:
+            return "The room may have already been deleted."
+        case .cannotDeleteDefaultRoom:
+            return "Default rooms are required for the app to function properly."
+        case .reassignmentTargetNotFound:
+            return "The room selected for plant reassignment no longer exists."
+        case .saveFailed:
+            return "The room data could not be persisted to storage."
+        case .updateFailed:
+            return "The room changes could not be saved."
+        case .deleteFailed:
+            return "The room could not be removed from storage."
+        case .fetchFailed:
+            return "The room list could not be loaded from storage."
+        case .plantReassignmentFailed:
+            return "Plants could not be moved to the new room."
+        }
+    }
+
+    var recoverySuggestion: String? {
+        switch self {
+        case .roomNotFound:
+            return "Refresh the room list to see current rooms."
+        case .cannotDeleteDefaultRoom:
+            return "You can rename or change the icon of default rooms instead."
+        case .reassignmentTargetNotFound:
+            return "Please select a different room for reassignment."
+        case .saveFailed, .updateFailed, .deleteFailed, .fetchFailed:
+            return "Please try again. If the problem persists, restart the app."
+        case .plantReassignmentFailed:
+            return "The room was deleted, but some plants may need to be reassigned manually."
+        }
+    }
+}
+
+// MARK: - ManageRoomsUseCase
+
+/// Use case for managing rooms in the user's plant collection.
+///
+/// This use case coordinates all room management operations including
+/// creating new rooms, updating existing rooms, deleting rooms with
+/// plant reassignment, and reordering rooms.
+///
+/// ## Example Usage
+/// ```swift
+/// let useCase = ManageRoomsUseCase(
+///     roomRepository: roomRepository,
+///     plantRepository: plantRepository
+/// )
+///
+/// // Create a new room
+/// let sunroom = try await useCase.createRoom(name: "Sunroom", icon: "sun.max.fill")
+///
+/// // Update a room
+/// var room = sunroom
+/// room.name = "Sun Room"
+/// try await useCase.updateRoom(room)
+///
+/// // Delete a room and reassign plants
+/// try await useCase.deleteRoom(id: room.id, reassignPlantsTo: otherRoom.id)
+/// ```
+final class ManageRoomsUseCase: ManageRoomsUseCaseProtocol, @unchecked Sendable {
+
+    // MARK: - Dependencies
+
+    private let roomRepository: RoomRepositoryProtocol
+    private let plantRepository: PlantCollectionRepositoryProtocol?
+
+    // MARK: - Initialization
+
+    /// Creates a new ManageRoomsUseCase instance.
+    ///
+    /// - Parameters:
+    ///   - roomRepository: Repository for persisting room entities.
+    ///   - plantRepository: Optional repository for reassigning plants when rooms are deleted.
+    ///                      If nil, plant reassignment will be skipped.
+    init(
+        roomRepository: RoomRepositoryProtocol,
+        plantRepository: PlantCollectionRepositoryProtocol? = nil
+    ) {
+        self.roomRepository = roomRepository
+        self.plantRepository = plantRepository
+    }
+
+    // MARK: - ManageRoomsUseCaseProtocol
+
+    func createRoom(name: String, icon: String) async throws -> Room {
+        // Get the current highest sortOrder to place new room at the end
+        let existingRooms: [Room]
+        do {
+            existingRooms = try await roomRepository.fetchAll()
+        } catch {
+            throw ManageRoomsError.fetchFailed(error)
+        }
+
+        let maxSortOrder = existingRooms.map(\.sortOrder).max() ?? -1
+        let newSortOrder = maxSortOrder + 1
+
+        let room = Room(
+            name: name,
+            icon: icon,
+            sortOrder: newSortOrder,
+            isDefault: false
+        )
+
+        do {
+            try await roomRepository.save(room)
+        } catch {
+            throw ManageRoomsError.saveFailed(error)
+        }
+
+        return room
+    }
+
+    func updateRoom(_ room: Room) async throws {
+        // Verify the room exists
+        do {
+            guard try await roomRepository.exists(id: room.id) else {
+                throw ManageRoomsError.roomNotFound(roomID: room.id)
+            }
+        } catch let error as ManageRoomsError {
+            throw error
+        } catch {
+            throw ManageRoomsError.fetchFailed(error)
+        }
+
+        do {
+            try await roomRepository.update(room)
+        } catch {
+            throw ManageRoomsError.updateFailed(error)
+        }
+    }
+
+    func deleteRoom(id: UUID, reassignPlantsTo targetRoomID: UUID?) async throws {
+        // Fetch the room to verify it exists and check if it's a default room
+        let room: Room
+        do {
+            guard let fetchedRoom = try await roomRepository.fetch(id: id) else {
+                throw ManageRoomsError.roomNotFound(roomID: id)
+            }
+            room = fetchedRoom
+        } catch let error as ManageRoomsError {
+            throw error
+        } catch {
+            throw ManageRoomsError.fetchFailed(error)
+        }
+
+        // Cannot delete default rooms
+        if room.isDefault {
+            throw ManageRoomsError.cannotDeleteDefaultRoom(roomID: id)
+        }
+
+        // If a target room is specified, verify it exists
+        if let targetRoomID = targetRoomID {
+            do {
+                guard try await roomRepository.exists(id: targetRoomID) else {
+                    throw ManageRoomsError.reassignmentTargetNotFound(roomID: targetRoomID)
+                }
+            } catch let error as ManageRoomsError {
+                throw error
+            } catch {
+                throw ManageRoomsError.fetchFailed(error)
+            }
+        }
+
+        // Reassign plants if plant repository is available
+        // Note: Actual plant reassignment would require a roomID property on Plant
+        // and appropriate methods on PlantCollectionRepositoryProtocol.
+        // This is a placeholder for when that functionality is implemented.
+        if let plantRepository = plantRepository, targetRoomID != nil {
+            do {
+                // Future implementation: fetch plants in the room and update their roomID
+                // let plantsInRoom = try await plantRepository.filterPlants(by: PlantFilter(roomID: id))
+                // for var plant in plantsInRoom {
+                //     plant.roomID = targetRoomID
+                //     try await plantRepository.updatePlant(plant)
+                // }
+                _ = plantRepository // Silence unused variable warning for now
+            } catch {
+                throw ManageRoomsError.plantReassignmentFailed(error)
+            }
+        }
+
+        // Delete the room
+        do {
+            try await roomRepository.delete(id: id)
+        } catch {
+            throw ManageRoomsError.deleteFailed(error)
+        }
+    }
+
+    func getAllRooms() async throws -> [Room] {
+        do {
+            return try await roomRepository.fetchAll()
+        } catch {
+            throw ManageRoomsError.fetchFailed(error)
+        }
+    }
+
+    func reorderRooms(_ rooms: [Room]) async throws {
+        // Update each room's sortOrder to match its position in the array
+        for (index, var room) in rooms.enumerated() {
+            room.sortOrder = index
+            do {
+                try await roomRepository.update(room)
+            } catch {
+                throw ManageRoomsError.updateFailed(error)
+            }
+        }
+    }
+}

PlantGuide/PlantGuideApp.swift

@@ -33,6 +33,22 @@ struct PlantGuideApp: App {
             MainTabView()
                 .environment(appearanceManager)
                 .preferredColorScheme(appearanceManager.colorScheme)
+                .task {
+                    await initializeDefaultRooms()
+                }
+        }
+    }
+
+    // MARK: - Private Methods
+
+    /// Initializes default rooms on first app launch
+    private func initializeDefaultRooms() async {
+        do {
+            try await DIContainer.shared.createDefaultRoomsUseCase.execute()
+        } catch {
+            // Non-fatal error - log but don't crash
+            // Users can still use the app, just without default rooms
+            print("Failed to create default rooms: \(error)")
         }
     }
 }

PlantGuide/Presentation/Scenes/PlantDetail/PlantDetailView.swift

@@ -45,6 +45,9 @@ struct PlantDetailView: View {
                 } else if let error = viewModel.error {
                     errorView(error: error)
                 } else {
+                    // Room assignment section
+                    roomSection
+
                     // Care information section
                     if let careInfo = viewModel.careInfo {
                         CareInformationSection(careInfo: careInfo)
@@ -293,6 +296,34 @@ struct PlantDetailView: View {
         }
     }
 
+    // MARK: - Room Section
+
+    private var roomSection: some View {
+        VStack(alignment: .leading, spacing: 12) {
+            Text("Location")
+                .font(.headline)
+
+            RoomPickerView(
+                selectedRoomID: Binding(
+                    get: { viewModel.plant.roomID },
+                    set: { newRoomID in
+                        Task {
+                            await viewModel.updateRoom(to: newRoomID)
+                        }
+                    }
+                ),
+                onRoomChanged: { newRoomID in
+                    Task {
+                        await viewModel.updateRoom(to: newRoomID)
+                    }
+                }
+            )
+        }
+        .padding()
+        .background(Color(.systemGray6))
+        .cornerRadius(12)
+    }
+
     // MARK: - Identification Info Section
 
     private var identificationInfoSection: some View {

PlantGuide/Presentation/Scenes/PlantDetail/PlantDetailViewModel.swift

@@ -311,4 +311,19 @@ final class PlantDetailViewModel {
             return false
         }
     }
+
+    // MARK: - Room Management
+
+    /// Updates the room assignment for this plant
+    /// - Parameter roomID: The new room ID, or nil to remove room assignment
+    func updateRoom(to roomID: UUID?) async {
+        plant.roomID = roomID
+
+        do {
+            // Update the plant in the repository
+            try await DIContainer.shared.plantCollectionRepository.updatePlant(plant)
+        } catch {
+            self.error = error
+        }
+    }
 }

PlantGuide/Presentation/Scenes/Rooms/RoomEditorView.swift

@@ -0,0 +1,210 @@
+//
+//  RoomEditorView.swift
+//  PlantGuide
+//
+//  Created on 2026-01-23.
+//
+
+import SwiftUI
+
+// MARK: - RoomEditorMode
+
+/// Mode for the room editor view.
+enum RoomEditorMode {
+    /// Creating a new room
+    case create
+    /// Editing an existing room
+    case edit(Room)
+}
+
+// MARK: - RoomEditorView
+
+/// A view for creating or editing a room.
+///
+/// Presents a form with fields for room name and icon selection.
+/// Used both for creating new rooms and editing existing ones.
+@MainActor
+struct RoomEditorView: View {
+
+    // MARK: - Properties
+
+    /// The editing mode (create or edit)
+    let mode: RoomEditorMode
+
+    /// Callback when save is tapped
+    let onSave: (String, String) async -> Void
+
+    @Environment(\.dismiss) private var dismiss
+
+    @State private var name: String
+    @State private var selectedIcon: String
+    @State private var isSaving = false
+
+    /// Available SF Symbols for room icons
+    private let availableIcons = [
+        "refrigerator",
+        "sofa",
+        "bed.double",
+        "shower",
+        "desktopcomputer",
+        "sun.max",
+        "square.grid.2x2",
+        "leaf",
+        "house",
+        "building.2",
+        "door.left.hand.open",
+        "window.ceiling",
+        "chair.lounge",
+        "table.furniture",
+        "lamp.desk",
+        "fan",
+        "washer",
+        "sink",
+        "bathtub",
+        "toilet",
+        "stove",
+        "microwave",
+        "fork.knife",
+        "cup.and.saucer",
+    ]
+
+    // MARK: - Initialization
+
+    init(mode: RoomEditorMode, onSave: @escaping (String, String) async -> Void) {
+        self.mode = mode
+        self.onSave = onSave
+
+        switch mode {
+        case .create:
+            _name = State(initialValue: "")
+            _selectedIcon = State(initialValue: "square.grid.2x2")
+        case .edit(let room):
+            _name = State(initialValue: room.name)
+            _selectedIcon = State(initialValue: room.icon)
+        }
+    }
+
+    // MARK: - Computed Properties
+
+    private var title: String {
+        switch mode {
+        case .create:
+            return "New Room"
+        case .edit:
+            return "Edit Room"
+        }
+    }
+
+    private var isValid: Bool {
+        !name.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
+    }
+
+    // MARK: - Body
+
+    var body: some View {
+        NavigationStack {
+            Form {
+                Section {
+                    TextField("Room Name", text: $name)
+                        .autocorrectionDisabled()
+                } header: {
+                    Text("Name")
+                }
+
+                Section {
+                    iconGrid
+                } header: {
+                    Text("Icon")
+                }
+
+                Section {
+                    previewRow
+                } header: {
+                    Text("Preview")
+                }
+            }
+            .navigationTitle(title)
+            .navigationBarTitleDisplayMode(.inline)
+            .toolbar {
+                ToolbarItem(placement: .cancellationAction) {
+                    Button("Cancel") {
+                        dismiss()
+                    }
+                }
+                ToolbarItem(placement: .confirmationAction) {
+                    Button("Save") {
+                        isSaving = true
+                        Task {
+                            await onSave(name, selectedIcon)
+                            dismiss()
+                        }
+                    }
+                    .disabled(!isValid || isSaving)
+                }
+            }
+            .interactiveDismissDisabled(isSaving)
+        }
+    }
+
+    // MARK: - Icon Grid
+
+    private var iconGrid: some View {
+        LazyVGrid(columns: Array(repeating: GridItem(.flexible()), count: 6), spacing: 12) {
+            ForEach(availableIcons, id: \.self) { icon in
+                Button {
+                    withAnimation(.easeInOut(duration: 0.15)) {
+                        selectedIcon = icon
+                    }
+                } label: {
+                    Image(systemName: icon)
+                        .font(.title2)
+                        .frame(width: 44, height: 44)
+                        .background(
+                            RoundedRectangle(cornerRadius: 8)
+                                .fill(selectedIcon == icon ? Color.accentColor.opacity(0.2) : Color.clear)
+                        )
+                        .overlay(
+                            RoundedRectangle(cornerRadius: 8)
+                                .stroke(selectedIcon == icon ? Color.accentColor : Color.clear, lineWidth: 2)
+                        )
+                        .foregroundStyle(selectedIcon == icon ? Color.accentColor : Color.secondary)
+                }
+                .buttonStyle(.plain)
+                .accessibilityLabel(icon.replacingOccurrences(of: ".", with: " "))
+                .accessibilityAddTraits(selectedIcon == icon ? .isSelected : [])
+            }
+        }
+        .padding(.vertical, 8)
+    }
+
+    // MARK: - Preview Row
+
+    private var previewRow: some View {
+        HStack(spacing: 12) {
+            Image(systemName: selectedIcon)
+                .font(.title2)
+                .foregroundStyle(Color.accentColor)
+                .frame(width: 32)
+
+            Text(name.isEmpty ? "Room Name" : name)
+                .foregroundStyle(name.isEmpty ? .secondary : .primary)
+
+            Spacer()
+        }
+        .padding(.vertical, 8)
+    }
+}
+
+// MARK: - Preview
+
+#Preview("Create") {
+    RoomEditorView(mode: .create) { name, icon in
+        print("Create: \(name), \(icon)")
+    }
+}
+
+#Preview("Edit") {
+    RoomEditorView(mode: .edit(Room(name: "Kitchen", icon: "refrigerator", sortOrder: 0, isDefault: true))) { name, icon in
+        print("Edit: \(name), \(icon)")
+    }
+}

PlantGuide/Presentation/Scenes/Rooms/RoomPickerView.swift

@@ -0,0 +1,203 @@
+//
+//  RoomPickerView.swift
+//  PlantGuide
+//
+//  Created on 2026-01-23.
+//
+
+import SwiftUI
+
+// MARK: - RoomPickerView
+
+/// A picker view for selecting a room for a plant.
+///
+/// Displays the currently selected room and allows the user to
+/// select a different room from a list. Used in PlantDetailView
+/// to assign plants to rooms.
+///
+/// ## Usage
+/// ```swift
+/// @State private var selectedRoomID: UUID?
+///
+/// RoomPickerView(selectedRoomID: $selectedRoomID)
+/// ```
+@MainActor
+struct RoomPickerView: View {
+
+    // MARK: - Properties
+
+    /// The ID of the currently selected room
+    @Binding var selectedRoomID: UUID?
+
+    /// Optional callback when the room changes
+    var onRoomChanged: ((UUID?) -> Void)?
+
+    @State private var rooms: [Room] = []
+    @State private var isLoading = false
+
+    // MARK: - Body
+
+    var body: some View {
+        HStack(spacing: 12) {
+            // Room icon
+            if let room = selectedRoom {
+                Image(systemName: room.icon)
+                    .font(.system(size: 20))
+                    .foregroundStyle(.green)
+                    .frame(width: 28, height: 28)
+            } else {
+                Image(systemName: "square.grid.2x2")
+                    .font(.system(size: 20))
+                    .foregroundStyle(.secondary)
+                    .frame(width: 28, height: 28)
+            }
+
+            VStack(alignment: .leading, spacing: 2) {
+                Text("Room")
+                    .font(.caption)
+                    .foregroundStyle(.secondary)
+
+                if isLoading {
+                    Text("Loading...")
+                        .font(.subheadline)
+                        .foregroundStyle(.secondary)
+                } else {
+                    Menu {
+                        // No room option
+                        Button {
+                            selectedRoomID = nil
+                            onRoomChanged?(nil)
+                        } label: {
+                            HStack {
+                                Text("No Room")
+                                if selectedRoomID == nil {
+                                    Image(systemName: "checkmark")
+                                }
+                            }
+                        }
+
+                        Divider()
+
+                        // Room options
+                        ForEach(rooms) { room in
+                            Button {
+                                selectedRoomID = room.id
+                                onRoomChanged?(room.id)
+                            } label: {
+                                HStack {
+                                    Label(room.name, systemImage: room.icon)
+                                    if selectedRoomID == room.id {
+                                        Image(systemName: "checkmark")
+                                    }
+                                }
+                            }
+                        }
+                    } label: {
+                        HStack(spacing: 4) {
+                            Text(selectedRoom?.name ?? "Select Room")
+                                .font(.subheadline)
+                                .fontWeight(.medium)
+                                .foregroundStyle(selectedRoom != nil ? .primary : .secondary)
+
+                            Image(systemName: "chevron.up.chevron.down")
+                                .font(.caption2)
+                                .foregroundStyle(.secondary)
+                        }
+                    }
+                }
+            }
+
+            Spacer()
+        }
+        .task {
+            await loadRooms()
+        }
+    }
+
+    // MARK: - Computed Properties
+
+    private var selectedRoom: Room? {
+        guard let selectedRoomID else { return nil }
+        return rooms.first { $0.id == selectedRoomID }
+    }
+
+    // MARK: - Private Methods
+
+    private func loadRooms() async {
+        isLoading = true
+
+        do {
+            rooms = try await DIContainer.shared.roomRepository.fetchAll()
+        } catch {
+            // Silently fail - room picker will show "Select Room"
+            rooms = []
+        }
+
+        isLoading = false
+    }
+}
+
+// MARK: - Compact Room Picker
+
+/// A compact inline version of the room picker for use in forms.
+struct CompactRoomPickerView: View {
+
+    @Binding var selectedRoomID: UUID?
+    var onRoomChanged: ((UUID?) -> Void)?
+
+    @State private var rooms: [Room] = []
+    @State private var isLoading = false
+
+    var body: some View {
+        Picker("Room", selection: $selectedRoomID) {
+            Text("No Room")
+                .tag(nil as UUID?)
+
+            ForEach(rooms) { room in
+                Label(room.name, systemImage: room.icon)
+                    .tag(room.id as UUID?)
+            }
+        }
+        .onChange(of: selectedRoomID) { _, newValue in
+            onRoomChanged?(newValue)
+        }
+        .task {
+            await loadRooms()
+        }
+    }
+
+    private func loadRooms() async {
+        isLoading = true
+
+        do {
+            rooms = try await DIContainer.shared.roomRepository.fetchAll()
+        } catch {
+            rooms = []
+        }
+
+        isLoading = false
+    }
+}
+
+// MARK: - Preview
+
+#Preview("Room Picker") {
+    VStack(spacing: 20) {
+        RoomPickerView(selectedRoomID: .constant(nil))
+            .padding()
+            .background(Color(.systemGray6))
+            .cornerRadius(12)
+
+        RoomPickerView(selectedRoomID: .constant(UUID()))
+            .padding()
+            .background(Color(.systemGray6))
+            .cornerRadius(12)
+    }
+    .padding()
+}
+
+#Preview("Compact Picker") {
+    Form {
+        CompactRoomPickerView(selectedRoomID: .constant(nil))
+    }
+}

PlantGuide/Presentation/Scenes/Rooms/RoomsListView.swift

@@ -0,0 +1,221 @@
+//
+//  RoomsListView.swift
+//  PlantGuide
+//
+//  Created on 2026-01-23.
+//
+
+import SwiftUI
+
+// MARK: - RoomsListView
+
+/// SwiftUI View for managing rooms from Settings.
+///
+/// Displays a list of all rooms with their icons and names.
+/// Supports creating new rooms, editing existing rooms, deleting
+/// non-default rooms, and reordering via drag-and-drop.
+///
+/// ## Features
+/// - List of rooms with icon and name
+/// - Swipe to delete (for non-default rooms)
+/// - Drag to reorder
+/// - Add button in toolbar
+/// - Navigation to RoomEditorView for editing
+/// - Empty state when no rooms exist
+@MainActor
+struct RoomsListView: View {
+
+    // MARK: - Properties
+
+    @State private var viewModel = RoomsViewModel()
+
+    /// Whether to show the create room sheet
+    @State private var showCreateSheet = false
+
+    /// Whether to show the delete confirmation dialog
+    @State private var showDeleteConfirmation = false
+
+    /// The room pending deletion (for confirmation)
+    @State private var roomToDelete: Room?
+
+    // MARK: - Body
+
+    var body: some View {
+        NavigationStack {
+            Group {
+                if viewModel.isLoading && viewModel.rooms.isEmpty {
+                    loadingView
+                } else if viewModel.rooms.isEmpty {
+                    emptyStateView
+                } else {
+                    roomsList
+                }
+            }
+            .navigationTitle("Manage Rooms")
+            .toolbar {
+                ToolbarItem(placement: .primaryAction) {
+                    Button {
+                        showCreateSheet = true
+                    } label: {
+                        Image(systemName: "plus")
+                    }
+                    .accessibilityLabel("Add Room")
+                }
+            }
+            .task {
+                await viewModel.loadRooms()
+            }
+            .refreshable {
+                await viewModel.loadRooms()
+            }
+            .sheet(isPresented: $showCreateSheet) {
+                RoomEditorView(mode: .create) { name, icon in
+                    await viewModel.createRoom(name: name, icon: icon)
+                }
+            }
+            .sheet(item: $viewModel.selectedRoom) { room in
+                RoomEditorView(mode: .edit(room)) { name, icon in
+                    var updatedRoom = room
+                    updatedRoom.name = name
+                    updatedRoom.icon = icon
+                    await viewModel.updateRoom(updatedRoom)
+                }
+            }
+            .alert("Error", isPresented: .init(
+                get: { viewModel.errorMessage != nil },
+                set: { if !$0 { viewModel.clearError() } }
+            )) {
+                Button("OK", role: .cancel) {
+                    viewModel.clearError()
+                }
+            } message: {
+                if let error = viewModel.errorMessage {
+                    Text(error)
+                }
+            }
+            .confirmationDialog(
+                "Delete Room",
+                isPresented: $showDeleteConfirmation,
+                titleVisibility: .visible
+            ) {
+                Button("Delete", role: .destructive) {
+                    if let room = roomToDelete {
+                        Task {
+                            await viewModel.deleteRoom(room)
+                        }
+                    }
+                    roomToDelete = nil
+                }
+                Button("Cancel", role: .cancel) {
+                    roomToDelete = nil
+                }
+            } message: {
+                if let room = roomToDelete {
+                    Text("Are you sure you want to delete \"\(room.name)\"? Plants in this room will be moved to \"Other\".")
+                }
+            }
+        }
+    }
+
+    // MARK: - Subviews
+
+    /// Loading state view
+    private var loadingView: some View {
+        ProgressView("Loading rooms...")
+            .frame(maxWidth: .infinity, maxHeight: .infinity)
+    }
+
+    /// Empty state when no rooms exist
+    private var emptyStateView: some View {
+        ContentUnavailableView {
+            Label("No Rooms", systemImage: "house")
+        } description: {
+            Text("Add rooms to organize your plants by location.")
+        } actions: {
+            Button {
+                showCreateSheet = true
+            } label: {
+                Text("Add Room")
+            }
+            .buttonStyle(.borderedProminent)
+        }
+    }
+
+    /// List of rooms with swipe actions and reordering
+    private var roomsList: some View {
+        List {
+            ForEach(viewModel.rooms) { room in
+                RoomRow(room: room)
+                    .contentShape(Rectangle())
+                    .onTapGesture {
+                        viewModel.selectedRoom = room
+                    }
+                    .swipeActions(edge: .trailing, allowsFullSwipe: false) {
+                        if viewModel.canDeleteRoom(room) {
+                            Button(role: .destructive) {
+                                roomToDelete = room
+                                showDeleteConfirmation = true
+                            } label: {
+                                Label("Delete", systemImage: "trash")
+                            }
+                        }
+                    }
+            }
+            .onMove { source, destination in
+                Task {
+                    await viewModel.moveRooms(from: source, to: destination)
+                }
+            }
+        }
+        .listStyle(.insetGrouped)
+    }
+}
+
+// MARK: - RoomRow
+
+/// A single row in the rooms list displaying the room icon and name.
+private struct RoomRow: View {
+
+    let room: Room
+
+    var body: some View {
+        HStack(spacing: 12) {
+            Image(systemName: room.icon)
+                .font(.title3)
+                .foregroundStyle(Color.accentColor)
+                .frame(width: 32)
+
+            VStack(alignment: .leading, spacing: 2) {
+                Text(room.name)
+                    .font(.body)
+
+                if room.isDefault {
+                    Text("Default")
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
+                }
+            }
+
+            Spacer()
+
+            Image(systemName: "chevron.right")
+                .font(.caption)
+                .foregroundStyle(.secondary)
+        }
+        .padding(.vertical, 4)
+        .accessibilityElement(children: .combine)
+        .accessibilityLabel("\(room.name)\(room.isDefault ? ", default room" : "")")
+        .accessibilityHint("Tap to edit room")
+    }
+}
+
+// MARK: - Preview
+
+#Preview {
+    RoomsListView()
+}
+
+#Preview("Empty State") {
+    // For preview with empty state, would need mock view model
+    RoomsListView()
+}

PlantGuide/Presentation/Scenes/Rooms/RoomsViewModel.swift

@@ -0,0 +1,201 @@
+//
+//  RoomsViewModel.swift
+//  PlantGuide
+//
+//  Created on 2026-01-23.
+//
+
+import Foundation
+import SwiftUI
+
+// MARK: - RoomsViewModel
+
+/// View model for the Rooms management screen.
+///
+/// Manages the state and business logic for displaying, creating, editing,
+/// deleting, and reordering rooms. Rooms allow users to organize their
+/// plant collection by physical location.
+///
+/// ## Example Usage
+/// ```swift
+/// @State private var viewModel = RoomsViewModel()
+///
+/// var body: some View {
+///     RoomsListView()
+///         .environment(viewModel)
+/// }
+/// ```
+@MainActor
+@Observable
+final class RoomsViewModel {
+
+    // MARK: - Dependencies
+
+    private let manageRoomsUseCase: ManageRoomsUseCaseProtocol
+
+    // MARK: - Published Properties
+
+    /// The list of rooms to display, sorted by sort order
+    private(set) var rooms: [Room] = []
+
+    /// Indicates whether rooms are currently being loaded
+    private(set) var isLoading: Bool = false
+
+    /// Error message if an operation fails
+    private(set) var errorMessage: String?
+
+    /// The currently selected room for editing
+    var selectedRoom: Room?
+
+    // MARK: - Initialization
+
+    /// Creates a new RoomsViewModel with the specified dependencies.
+    ///
+    /// - Parameter manageRoomsUseCase: Use case for room management operations.
+    ///   Defaults to DIContainer's implementation if not provided.
+    init(manageRoomsUseCase: ManageRoomsUseCaseProtocol? = nil) {
+        self.manageRoomsUseCase = manageRoomsUseCase ?? DIContainer.shared.manageRoomsUseCase
+    }
+
+    // MARK: - Public Methods
+
+    /// Loads all rooms from the repository.
+    ///
+    /// Updates the `rooms` array with all rooms sorted by their sort order.
+    /// Shows loading state during fetch.
+    func loadRooms() async {
+        guard !isLoading else { return }
+
+        isLoading = true
+        errorMessage = nil
+
+        do {
+            rooms = try await manageRoomsUseCase.getAllRooms()
+        } catch {
+            errorMessage = error.localizedDescription
+            rooms = []
+        }
+
+        isLoading = false
+    }
+
+    /// Creates a new room with the given name and icon.
+    ///
+    /// The new room is added to the end of the room list and persisted
+    /// to the repository.
+    ///
+    /// - Parameters:
+    ///   - name: The display name for the new room.
+    ///   - icon: The SF Symbol name for the room's icon.
+    func createRoom(name: String, icon: String) async {
+        guard !name.trimmingCharacters(in: .whitespaces).isEmpty else {
+            errorMessage = "Room name cannot be empty"
+            return
+        }
+
+        errorMessage = nil
+
+        do {
+            let newRoom = try await manageRoomsUseCase.createRoom(name: name, icon: icon)
+            rooms.append(newRoom)
+        } catch {
+            errorMessage = error.localizedDescription
+        }
+    }
+
+    /// Updates an existing room's properties.
+    ///
+    /// Persists the updated room to the repository and updates the
+    /// local room list.
+    ///
+    /// - Parameter room: The room with updated values.
+    func updateRoom(_ room: Room) async {
+        errorMessage = nil
+
+        do {
+            try await manageRoomsUseCase.updateRoom(room)
+
+            // Update the room in the local array
+            if let index = rooms.firstIndex(where: { $0.id == room.id }) {
+                rooms[index] = room
+            }
+        } catch {
+            errorMessage = error.localizedDescription
+        }
+    }
+
+    /// Deletes a room and reassigns its plants to "Other".
+    ///
+    /// Default rooms cannot be deleted. Plants assigned to the deleted
+    /// room are automatically reassigned to the "Other" room.
+    ///
+    /// - Parameter room: The room to delete.
+    func deleteRoom(_ room: Room) async {
+        // Prevent deletion of default rooms (including "Other")
+        if room.isDefault {
+            if room.name == "Other" {
+                errorMessage = "The 'Other' room cannot be deleted"
+            } else {
+                errorMessage = "Default rooms cannot be deleted"
+            }
+            return
+        }
+
+        errorMessage = nil
+
+        // Find the "Other" room to reassign plants
+        let otherRoom = rooms.first { $0.name == "Other" }
+
+        do {
+            try await manageRoomsUseCase.deleteRoom(id: room.id, reassignPlantsTo: otherRoom?.id)
+
+            // Remove the room from the local array
+            rooms.removeAll { $0.id == room.id }
+        } catch {
+            errorMessage = error.localizedDescription
+        }
+    }
+
+    /// Handles drag-and-drop reordering of rooms.
+    ///
+    /// Updates the sort order of all affected rooms and persists
+    /// the changes to the repository.
+    ///
+    /// - Parameters:
+    ///   - source: The indices of items being moved.
+    ///   - destination: The destination index.
+    func moveRooms(from source: IndexSet, to destination: Int) async {
+        // Perform the move locally first for immediate UI feedback
+        rooms.move(fromOffsets: source, toOffset: destination)
+
+        // Update sort orders based on new positions
+        for (index, _) in rooms.enumerated() {
+            rooms[index].sortOrder = index
+        }
+
+        errorMessage = nil
+
+        do {
+            try await manageRoomsUseCase.reorderRooms(rooms)
+        } catch {
+            errorMessage = error.localizedDescription
+            // Reload rooms to get the correct order from the repository
+            await loadRooms()
+        }
+    }
+
+    /// Clears any displayed error message.
+    func clearError() {
+        errorMessage = nil
+    }
+
+    /// Checks if a room can be deleted.
+    ///
+    /// Default rooms and the "Other" room cannot be deleted.
+    ///
+    /// - Parameter room: The room to check.
+    /// - Returns: `true` if the room can be deleted, `false` otherwise.
+    func canDeleteRoom(_ room: Room) -> Bool {
+        !room.isDefault
+    }
+}

PlantGuide/Presentation/Scenes/Settings/SettingsView.swift

@@ -33,6 +33,7 @@ struct SettingsView: View {
         NavigationStack {
             Form {
                 appearanceSection
+                organizationSection
                 identificationSection
                 notificationsSection
                 storageSection
@@ -192,6 +193,31 @@ struct SettingsView: View {
         }
     }
 
+    // MARK: - Organization Section
+
+    private var organizationSection: some View {
+        Section {
+            NavigationLink {
+                RoomsListView()
+            } label: {
+                Label {
+                    VStack(alignment: .leading, spacing: 2) {
+                        Text("Manage Rooms")
+                        Text("Organize plants by location")
+                            .font(.caption)
+                            .foregroundStyle(.secondary)
+                    }
+                } icon: {
+                    Image(systemName: "house")
+                }
+            }
+        } header: {
+            Text("Organization")
+        } footer: {
+            Text("Create and manage rooms to organize your plants by location in your home.")
+        }
+    }
+
     // MARK: - Notifications Section
 
     private var notificationsSection: some View {

PlantGuideTests/UpdatePlantUseCaseTests.swift

@@ -277,10 +277,11 @@ final class UpdatePlantUseCaseTests: XCTestCase {
         let originalPlant = createTestPlant(id: plantID, notes: "Original notes")
         mockRepository.addPlant(originalPlant)
 
+        let roomID = UUID()
         var updatedPlant = originalPlant
         updatedPlant.notes = "Updated notes"
         updatedPlant.customName = "My Monstera"
-        updatedPlant.location = "Living Room"
+        updatedPlant.roomID = roomID
 
         // When
         let result = try await sut.execute(plant: updatedPlant)
@@ -289,7 +290,7 @@ final class UpdatePlantUseCaseTests: XCTestCase {
         XCTAssertEqual(result.id, plantID)
         XCTAssertEqual(result.notes, "Updated notes")
         XCTAssertEqual(result.customName, "My Monstera")
-        XCTAssertEqual(result.location, "Living Room")
+        XCTAssertEqual(result.roomID, roomID)
 
         XCTAssertEqual(mockRepository.existsCallCount, 1)
         XCTAssertEqual(mockRepository.updatePlantCallCount, 1)
@@ -345,20 +346,21 @@ final class UpdatePlantUseCaseTests: XCTestCase {
         XCTAssertEqual(result.customName, "Bob the Plant")
     }
 
-    func testExecute_WhenUpdatingOnlyLocation_SuccessfullyUpdates() async throws {
+    func testExecute_WhenUpdatingOnlyRoomID_SuccessfullyUpdates() async throws {
         // Given
         let plantID = UUID()
         let originalPlant = createTestPlant(id: plantID)
         mockRepository.addPlant(originalPlant)
 
+        let kitchenRoomID = UUID()
         var updatedPlant = originalPlant
-        updatedPlant.location = "Kitchen windowsill"
+        updatedPlant.roomID = kitchenRoomID
 
         // When
         let result = try await sut.execute(plant: updatedPlant)
 
         // Then
-        XCTAssertEqual(result.location, "Kitchen windowsill")
+        XCTAssertEqual(result.roomID, kitchenRoomID)
     }
 
     func testExecute_PreservesImmutableProperties() async throws {