diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -302,7 +302,6 @@
   __coroutine/trivial_awaitables.h
   __debug
   __debug_utils/randomize_range.h
-  __errc
   __exception/exception.h
   __exception/exception_ptr.h
   __exception/nested_exception.h
@@ -589,6 +588,7 @@
   __support/xlocale/__nop_locale_mgmt.h
   __support/xlocale/__posix_l_fallback.h
   __support/xlocale/__strtonum_fallback.h
+  __system_error/errc.h
   __thread/poll_with_backoff.h
   __thread/timed_backoff_policy.h
   __threading_support
diff --git a/libcxx/include/__charconv/from_chars_integral.h b/libcxx/include/__charconv/from_chars_integral.h
--- a/libcxx/include/__charconv/from_chars_integral.h
+++ b/libcxx/include/__charconv/from_chars_integral.h
@@ -14,8 +14,8 @@
 #include <__charconv/from_chars_result.h>
 #include <__charconv/traits.h>
 #include <__config>
-#include <__errc>
 #include <__memory/addressof.h>
+#include <__system_error/errc.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/integral_constant.h>
 #include <__type_traits/is_integral.h>
diff --git a/libcxx/include/__charconv/from_chars_result.h b/libcxx/include/__charconv/from_chars_result.h
--- a/libcxx/include/__charconv/from_chars_result.h
+++ b/libcxx/include/__charconv/from_chars_result.h
@@ -11,7 +11,7 @@
 #define _LIBCPP___CHARCONV_FROM_CHARS_RESULT_H
 
 #include <__config>
-#include <__errc>
+#include <__system_error/errc.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
diff --git a/libcxx/include/__charconv/to_chars_integral.h b/libcxx/include/__charconv/to_chars_integral.h
--- a/libcxx/include/__charconv/to_chars_integral.h
+++ b/libcxx/include/__charconv/to_chars_integral.h
@@ -17,7 +17,7 @@
 #include <__charconv/to_chars_result.h>
 #include <__charconv/traits.h>
 #include <__config>
-#include <__errc>
+#include <__system_error/errc.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/integral_constant.h>
 #include <__type_traits/is_same.h>
diff --git a/libcxx/include/__charconv/to_chars_result.h b/libcxx/include/__charconv/to_chars_result.h
--- a/libcxx/include/__charconv/to_chars_result.h
+++ b/libcxx/include/__charconv/to_chars_result.h
@@ -11,7 +11,7 @@
 #define _LIBCPP___CHARCONV_TO_CHARS_RESULT_H
 
 #include <__config>
-#include <__errc>
+#include <__system_error/errc.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
diff --git a/libcxx/include/__filesystem/directory_entry.h b/libcxx/include/__filesystem/directory_entry.h
--- a/libcxx/include/__filesystem/directory_entry.h
+++ b/libcxx/include/__filesystem/directory_entry.h
@@ -13,7 +13,6 @@
 #include <__availability>
 #include <__chrono/time_point.h>
 #include <__config>
-#include <__errc>
 #include <__filesystem/file_status.h>
 #include <__filesystem/file_time_type.h>
 #include <__filesystem/file_type.h>
@@ -21,6 +20,7 @@
 #include <__filesystem/operations.h>
 #include <__filesystem/path.h>
 #include <__filesystem/perms.h>
+#include <__system_error/errc.h>
 #include <__utility/unreachable.h>
 #include <cstdint>
 #include <cstdlib>
diff --git a/libcxx/include/__format/formatter_floating_point.h b/libcxx/include/__format/formatter_floating_point.h
--- a/libcxx/include/__format/formatter_floating_point.h
+++ b/libcxx/include/__format/formatter_floating_point.h
@@ -22,7 +22,6 @@
 #include <__concepts/arithmetic.h>
 #include <__concepts/same_as.h>
 #include <__config>
-#include <__errc>
 #include <__format/concepts.h>
 #include <__format/format_parse_context.h>
 #include <__format/formatter.h>
@@ -30,6 +29,7 @@
 #include <__format/formatter_output.h>
 #include <__format/parser_std_format_spec.h>
 #include <__memory/allocator.h>
+#include <__system_error/errc.h>
 #include <__type_traits/conditional.h>
 #include <__utility/move.h>
 #include <__utility/unreachable.h>
diff --git a/libcxx/include/__format/formatter_integral.h b/libcxx/include/__format/formatter_integral.h
--- a/libcxx/include/__format/formatter_integral.h
+++ b/libcxx/include/__format/formatter_integral.h
@@ -16,11 +16,11 @@
 #include <__concepts/arithmetic.h>
 #include <__concepts/same_as.h>
 #include <__config>
-#include <__errc>
 #include <__format/concepts.h>
 #include <__format/format_error.h>
 #include <__format/formatter_output.h>
 #include <__format/parser_std_format_spec.h>
+#include <__system_error/errc.h>
 #include <__type_traits/make_unsigned.h>
 #include <__utility/unreachable.h>
 #include <array>
diff --git a/libcxx/include/__format/formatter_output.h b/libcxx/include/__format/formatter_output.h
--- a/libcxx/include/__format/formatter_output.h
+++ b/libcxx/include/__format/formatter_output.h
@@ -19,7 +19,6 @@
 #include <__chrono/statically_widen.h>
 #include <__concepts/same_as.h>
 #include <__config>
-#include <__errc>
 #include <__format/buffer.h>
 #include <__format/concepts.h>
 #include <__format/escaped_output_table.h>
@@ -29,6 +28,7 @@
 #include <__iterator/back_insert_iterator.h>
 #include <__iterator/concepts.h>
 #include <__iterator/readable_traits.h> // iter_value_t
+#include <__system_error/errc.h>
 #include <__type_traits/make_unsigned.h>
 #include <__utility/move.h>
 #include <__utility/unreachable.h>
diff --git a/libcxx/include/__errc b/libcxx/include/__system_error/errc.h
rename from libcxx/include/__errc
rename to libcxx/include/__system_error/errc.h
diff --git a/libcxx/include/charconv b/libcxx/include/charconv
--- a/libcxx/include/charconv
+++ b/libcxx/include/charconv
@@ -80,7 +80,7 @@
 #include <__charconv/traits.h>
 #include <__config>
 #include <__debug>
-#include <__errc>
+#include <__system_error/errc.h>
 #include <cmath> // for log2f
 #include <cstdint>
 #include <cstdlib>
diff --git a/libcxx/include/libcxx.imp b/libcxx/include/libcxx.imp
--- a/libcxx/include/libcxx.imp
+++ b/libcxx/include/libcxx.imp
@@ -41,6 +41,7 @@
   { include: [ "@<__ranges/.*>", "private", "<ranges>", "public" ] },
   { include: [ "@<__string/.*>", "private", "<string>", "public" ] },
   { include: [ "@<__support/.*>", "private", "<support>", "public" ] },
+  { include: [ "@<__system_error/.*>", "private", "<system_error>", "public" ] },
   { include: [ "@<__thread/.*>", "private", "<thread>", "public" ] },
   { include: [ "@<__tuple_dir/.*>", "private", "<tuple>", "public" ] },
   { include: [ "@<__type_traits/.*>", "private", "<type_traits>", "public" ] },
diff --git a/libcxx/include/module.modulemap.in b/libcxx/include/module.modulemap.in
--- a/libcxx/include/module.modulemap.in
+++ b/libcxx/include/module.modulemap.in
@@ -1434,6 +1434,10 @@
   module system_error {
     header "system_error"
     export *
+
+    module __system_error {
+      module errc { private header "__system_error/errc.h" }
+    }
   }
   module thread {
     @requires_LIBCXX_ENABLE_THREADS@
@@ -1699,7 +1703,6 @@
   module __availability      { private header "__availability"      export * }
   module __bit_reference     { private header "__bit_reference"     export * }
   module __debug             {         header "__debug"             export * }
-  module __errc              { private header "__errc"              export * }
   module __hash_table        {         header "__hash_table"        export * }
   module __locale            {
     @requires_LIBCXX_ENABLE_LOCALIZATION@
diff --git a/libcxx/include/system_error b/libcxx/include/system_error
--- a/libcxx/include/system_error
+++ b/libcxx/include/system_error
@@ -146,10 +146,10 @@
 
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
-#include <__errc>
 #include <__functional/hash.h>
 #include <__functional/unary_function.h>
 #include <__memory/addressof.h>
+#include <__system_error/errc.h>
 #include <stdexcept>
 #include <string>
 #include <version>
diff --git a/libcxx/src/include/ryu/ryu.h b/libcxx/src/include/ryu/ryu.h
--- a/libcxx/src/include/ryu/ryu.h
+++ b/libcxx/src/include/ryu/ryu.h
@@ -48,7 +48,7 @@
 #include <__charconv/to_chars_result.h>
 #include <__config>
 #include <__debug>
-#include <__errc>
+#include <__system_error/errc.h>
 #include <cstdint>
 #include <cstring>
 #include <type_traits>
diff --git a/libcxx/test/libcxx/private_headers.verify.cpp b/libcxx/test/libcxx/private_headers.verify.cpp
--- a/libcxx/test/libcxx/private_headers.verify.cpp
+++ b/libcxx/test/libcxx/private_headers.verify.cpp
@@ -334,7 +334,6 @@
 #include <__coroutine/noop_coroutine_handle.h> // expected-error@*:* {{use of private header from outside its module: '__coroutine/noop_coroutine_handle.h'}}
 #include <__coroutine/trivial_awaitables.h> // expected-error@*:* {{use of private header from outside its module: '__coroutine/trivial_awaitables.h'}}
 #include <__debug_utils/randomize_range.h> // expected-error@*:* {{use of private header from outside its module: '__debug_utils/randomize_range.h'}}
-#include <__errc> // expected-error@*:* {{use of private header from outside its module: '__errc'}}
 #include <__exception/exception.h> // expected-error@*:* {{use of private header from outside its module: '__exception/exception.h'}}
 #include <__exception/exception_ptr.h> // expected-error@*:* {{use of private header from outside its module: '__exception/exception_ptr.h'}}
 #include <__exception/nested_exception.h> // expected-error@*:* {{use of private header from outside its module: '__exception/nested_exception.h'}}
@@ -604,6 +603,7 @@
 #include <__string/char_traits.h> // expected-error@*:* {{use of private header from outside its module: '__string/char_traits.h'}}
 #include <__string/constexpr_c_functions.h> // expected-error@*:* {{use of private header from outside its module: '__string/constexpr_c_functions.h'}}
 #include <__string/extern_template_lists.h> // expected-error@*:* {{use of private header from outside its module: '__string/extern_template_lists.h'}}
+#include <__system_error/errc.h> // expected-error@*:* {{use of private header from outside its module: '__system_error/errc.h'}}
 #include <__thread/poll_with_backoff.h> // expected-error@*:* {{use of private header from outside its module: '__thread/poll_with_backoff.h'}}
 #include <__thread/timed_backoff_policy.h> // expected-error@*:* {{use of private header from outside its module: '__thread/timed_backoff_policy.h'}}
 #include <__tuple_dir/apply_cv.h> // expected-error@*:* {{use of private header from outside its module: '__tuple_dir/apply_cv.h'}}
diff --git a/libcxx/utils/data/ignore_format.txt b/libcxx/utils/data/ignore_format.txt
--- a/libcxx/utils/data/ignore_format.txt
+++ b/libcxx/utils/data/ignore_format.txt
@@ -308,7 +308,6 @@
 libcxx/include/__debug
 libcxx/include/__debug_utils/randomize_range.h
 libcxx/include/deque
-libcxx/include/__errc
 libcxx/include/errno.h
 libcxx/include/execution
 libcxx/include/expected
@@ -611,6 +610,7 @@
 libcxx/include/__support/solaris/xlocale.h
 libcxx/include/__support/win32/locale_win32.h
 libcxx/include/__support/xlocale/__nop_locale_mgmt.h
+libcxx/include/__system_error/errc.h
 libcxx/include/system_error
 libcxx/include/thread
 libcxx/include/__threading_support