diff --git a/stl/CMakeLists.txt b/stl/CMakeLists.txt
index 9596c5d169..ef34a76356 100644
--- a/stl/CMakeLists.txt
+++ b/stl/CMakeLists.txt
@@ -7,6 +7,7 @@ set(HEADERS
     ${CMAKE_CURRENT_LIST_DIR}/inc/any
     ${CMAKE_CURRENT_LIST_DIR}/inc/array
     ${CMAKE_CURRENT_LIST_DIR}/inc/atomic
+    ${CMAKE_CURRENT_LIST_DIR}/inc/bit
     ${CMAKE_CURRENT_LIST_DIR}/inc/bitset
     ${CMAKE_CURRENT_LIST_DIR}/inc/cassert
     ${CMAKE_CURRENT_LIST_DIR}/inc/ccomplex
diff --git a/stl/inc/__msvc_all_public_headers.hpp b/stl/inc/__msvc_all_public_headers.hpp
index 66688081eb..1776787134 100644
--- a/stl/inc/__msvc_all_public_headers.hpp
+++ b/stl/inc/__msvc_all_public_headers.hpp
@@ -40,6 +40,7 @@
 #include <algorithm>
 #include <any>
 #include <array>
+#include <bit>
 #include <bitset>
 #include <charconv>
 #include <chrono>
diff --git a/stl/inc/bit b/stl/inc/bit
new file mode 100644
index 0000000000..4db71a6390
--- /dev/null
+++ b/stl/inc/bit
@@ -0,0 +1,33 @@
+// bit standard header (core)
+
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#pragma once
+#ifndef _BIT_
+#define _BIT_
+#include <yvals_core.h>
+#if _STL_COMPILER_PREPROCESSOR
+#if !_HAS_CXX20
+#pragma message("The contents of <bit> are available only with C++20 or later.")
+#else // ^^^ !_HAS_CXX20 / _HAS_CXX20 vvv
+
+#pragma pack(push, _CRT_PACKING)
+#pragma warning(push, _STL_WARNING_LEVEL)
+#pragma warning(disable : _STL_DISABLED_WARNINGS)
+_STL_DISABLE_CLANG_WARNINGS
+#pragma push_macro("new")
+#undef new
+
+_STD_BEGIN
+enum class endian { little = 0, big = 1, native = little };
+
+_STD_END
+
+#pragma pop_macro("new")
+_STL_RESTORE_CLANG_WARNINGS
+#pragma warning(pop)
+#pragma pack(pop)
+#endif // _HAS_CXX20
+#endif // _STL_COMPILER_PREPROCESSOR
+#endif // _BIT_
diff --git a/stl/inc/type_traits b/stl/inc/type_traits
index 190994f281..bed0e166bf 100644
--- a/stl/inc/type_traits
+++ b/stl/inc/type_traits
@@ -72,11 +72,6 @@ struct negation : bool_constant<!static_cast<bool>(_Trait::value)> {}; // The ne
 template <class _Trait>
 _INLINE_VAR constexpr bool negation_v = negation<_Trait>::value;
 
-#if _HAS_CXX20
-// ENUM CLASS endian
-enum class endian { little = 0, big = 1, native = little };
-#endif // _HAS_CXX20
-
 // STRUCT TEMPLATE _Arg_types
 template <class... _Types>
 struct _Arg_types {}; // provide argument_type, etc. (sometimes)
diff --git a/stl/inc/yvals_core.h b/stl/inc/yvals_core.h
index 9412cc07ae..88df38ed05 100644
--- a/stl/inc/yvals_core.h
+++ b/stl/inc/yvals_core.h
@@ -52,6 +52,7 @@
 // P1227R2 Signed std::ssize(), Unsigned span::size()
 //     (partially implemented)
 // P1357R1 is_bounded_array, is_unbounded_array
+// P1612R1 Relocating endian To <bit>
 // P1651R0 bind_front() Should Not Unwrap reference_wrapper
 // P1754R1 Rename Concepts To standard_case
 // P????R? directory_entry::clear_cache()
@@ -959,6 +960,7 @@
 #endif // _HAS_STD_BOOLEAN
 #endif // defined(__cpp_concepts) && __cpp_concepts > 201507L
 
+#define __cpp_lib_endian                   201907L
 #define __cpp_lib_erase_if                 201811L
 #define __cpp_lib_generic_unordered_lookup 201811L
 #define __cpp_lib_list_remove_return_type  201806L