HierarchyId

EF Core 8, 9, and 10

Install the NuGet package:

Install-Package Microsoft.EntityFrameworkCore.SqlServer.HierarchyId

Add .UseHierarchyId() when configuring the DbContext:

// Via DbContextOptionsBuilder
var optionsBuilder = new DbContextOptionsBuilder<MyDbContext>()
    .UseSqlServer(@"your_connection_string", x => x.UseHierarchyId());

// Via dependency injection / Startup.cs
services.AddDbContext<MyDbContext>(options =>
    options.UseSqlServer(connectionString, x => x.UseHierarchyId()));

Combined with NetTopologySuite spatial types:

optionsBuilder.UseSqlServer(@"...", x => x.UseNetTopologySuite().UseHierarchyId().MaxBatchSize(100));

EF 6

HierarchyId is natively supported in the latest EntityFramework NuGet package — no additional packages required.

Note: If you use both HierarchyId AND table-valued functions in EF 6, you need to compile CodeFirstStoreFunctions against EntityFrameworkWithHierarchyId rather than EntityFramework.