diff --git a/src/Microsoft.AspNetCore.Http.Abstractions/StatusCodes.cs b/src/Microsoft.AspNetCore.Http.Abstractions/StatusCodes.cs
index 6129ea699f..0d169b1982 100644
--- a/src/Microsoft.AspNetCore.Http.Abstractions/StatusCodes.cs
+++ b/src/Microsoft.AspNetCore.Http.Abstractions/StatusCodes.cs
@@ -47,6 +47,7 @@ namespace Microsoft.AspNetCore.Http
         public const int Status422UnprocessableEntity = 422;
         public const int Status423Locked = 423;
         public const int Status424FailedDependency = 424;
+        public const int Status451UnavailableForLegalReasons = 451;
 
         public const int Status500InternalServerError = 500;
         public const int Status501NotImplemented = 501;