diff --git a/cc/toolchains/features/BUILD b/cc/toolchains/features/BUILD
new file mode 100644
index 0000000..c9ad527
--- /dev/null
+++ b/cc/toolchains/features/BUILD
@@ -0,0 +1,98 @@
+load("//cc/toolchains:feature_set.bzl", "cc_feature_set")
+load("//cc/toolchains/impl:external_feature.bzl", "cc_external_feature")
+
+package(default_visibility = ["//visibility:public"])
+
+# See https://bazel.build/docs/cc-toolchain-config-reference#wellknown-features
+
+cc_external_feature(
+    name = "opt",
+    feature_name = "opt",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "dbg",
+    feature_name = "dbg",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "fastbuild",
+    feature_name = "fastbuild",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "static_linking_mode",
+    feature_name = "static_linking_mode",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "dynamic_linking_mode",
+    feature_name = "dynamic_linking_mode",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "per_object_debug_info",
+    feature_name = "per_object_debug_info",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "supports_start_end_lib",
+    feature_name = "supports_start_end_lib",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "supports_interface_shared_libraries",
+    feature_name = "supports_interface_shared_libraries",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "supports_dynamic_linker",
+    feature_name = "supports_dynamic_linker",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "static_link_cpp_runtimes",
+    feature_name = "static_link_cpp_runtimes",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "supports_pic",
+    feature_name = "supports_pic",
+    overridable = True,
+)
+
+cc_feature_set(
+    name = "all_non_legacy_builtin_features",
+    features = [
+        ":opt",
+        ":dbg",
+        ":fastbuild",
+        ":static_linking_mode",
+        ":dynamic_linking_mode",
+        ":per_object_debug_info",
+        ":supports_start_end_lib",
+        ":supports_interface_shared_libraries",
+        ":supports_dynamic_linker",
+        ":static_link_cpp_runtimes",
+        ":supports_pic",
+    ],
+    visibility = ["//visibility:private"],
+)
+
+cc_feature_set(
+    name = "all_builtin_features",
+    features = [
+        ":all_non_legacy_builtin_features",
+        "//cc/toolchains/features/legacy:all_legacy_builtin_features",
+    ],
+)
diff --git a/cc/toolchains/features/legacy/BUILD b/cc/toolchains/features/legacy/BUILD
new file mode 100644
index 0000000..60d9613
--- /dev/null
+++ b/cc/toolchains/features/legacy/BUILD
@@ -0,0 +1,279 @@
+load("//cc/toolchains:feature_set.bzl", "cc_feature_set")
+load("//cc/toolchains/impl:external_feature.bzl", "cc_external_feature")
+
+package(default_visibility = ["//visibility:public"])
+
+# See https://bazel.build/docs/cc-toolchain-config-reference#wellknown-features.
+
+cc_external_feature(
+    name = "legacy_compile_flags",
+    feature_name = "legacy_compile_flags",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "default_compile_flags",
+    feature_name = "default_compile_flags",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "dependency_file",
+    feature_name = "dependency_file",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "pic",
+    feature_name = "pic",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "preprocessor_defines",
+    feature_name = "preprocessor_defines",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "includes",
+    feature_name = "includes",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "include_paths",
+    feature_name = "include_paths",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "fdo_instrument",
+    feature_name = "fdo_instrument",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "fdo_optimize",
+    feature_name = "fdo_optimize",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "cs_fdo_instrument",
+    feature_name = "cs_fdo_instrument",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "cs_fdo_optimize",
+    feature_name = "cs_fdo_optimize",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "fdo_prefetch_hints",
+    feature_name = "fdo_prefetch_hints",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "autofdo",
+    feature_name = "autofdo",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "build_interface_libraries",
+    feature_name = "build_interface_libraries",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "dynamic_library_linker_tool",
+    feature_name = "dynamic_library_linker_tool",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "shared_flag",
+    feature_name = "shared_flag",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "linkstamps",
+    feature_name = "linkstamps",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "output_execpath_flags",
+    feature_name = "output_execpath_flags",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "runtime_library_search_directories",
+    feature_name = "runtime_library_search_directories",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "library_search_directories",
+    feature_name = "library_search_directories",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "archiver_flags",
+    feature_name = "archiver_flags",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "libraries_to_link",
+    feature_name = "libraries_to_link",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "force_pic_flags",
+    feature_name = "force_pic_flags",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "user_link_flags",
+    feature_name = "user_link_flags",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "legacy_link_flags",
+    feature_name = "legacy_link_flags",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "static_libgcc",
+    feature_name = "static_libgcc",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "fission_support",
+    feature_name = "fission_support",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "strip_debug_symbols",
+    feature_name = "strip_debug_symbols",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "coverage",
+    feature_name = "coverage",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "llvm_coverage_map_format",
+    feature_name = "llvm_coverage_map_format",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "gcc_coverage_map_format",
+    feature_name = "gcc_coverage_map_format",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "fully_static_link",
+    feature_name = "fully_static_link",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "user_compile_flags",
+    feature_name = "user_compile_flags",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "sysroot",
+    feature_name = "sysroot",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "unfiltered_compile_flags",
+    feature_name = "unfiltered_compile_flags",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "linker_param_file",
+    feature_name = "linker_param_file",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "compiler_input_flags",
+    feature_name = "compiler_input_flags",
+    overridable = True,
+)
+
+cc_external_feature(
+    name = "compiler_output_flags",
+    feature_name = "compiler_output_flags",
+    overridable = True,
+)
+
+cc_feature_set(
+    name = "all_legacy_builtin_features",
+    features = [
+        ":legacy_compile_flags",
+        ":default_compile_flags",
+        ":dependency_file",
+        ":pic",
+        ":preprocessor_defines",
+        ":includes",
+        ":include_paths",
+        ":fdo_instrument",
+        ":fdo_optimize",
+        ":cs_fdo_instrument",
+        ":cs_fdo_optimize",
+        ":fdo_prefetch_hints",
+        ":autofdo",
+        ":build_interface_libraries",
+        ":dynamic_library_linker_tool",
+        ":shared_flag",
+        ":linkstamps",
+        ":output_execpath_flags",
+        ":runtime_library_search_directories",
+        ":library_search_directories",
+        ":archiver_flags",
+        ":libraries_to_link",
+        ":force_pic_flags",
+        ":user_link_flags",
+        ":legacy_link_flags",
+        ":static_libgcc",
+        ":fission_support",
+        ":strip_debug_symbols",
+        ":coverage",
+        ":llvm_coverage_map_format",
+        ":gcc_coverage_map_format",
+        ":fully_static_link",
+        ":user_compile_flags",
+        ":sysroot",
+        ":unfiltered_compile_flags",
+        ":linker_param_file",
+        ":compiler_input_flags",
+        ":compiler_output_flags",
+    ],
+    visibility = ["//cc/toolchains/features:__pkg__"],
+)
diff --git a/cc/toolchains/impl/external_feature.bzl b/cc/toolchains/impl/external_feature.bzl
new file mode 100644
index 0000000..0853b32
--- /dev/null
+++ b/cc/toolchains/impl/external_feature.bzl
@@ -0,0 +1,72 @@
+# Copyright 2024 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Implementation of the cc_external_feature rule."""
+
+load(
+    "//cc/toolchains:cc_toolchain_info.bzl",
+    "ArgsListInfo",
+    "FeatureConstraintInfo",
+    "FeatureInfo",
+    "FeatureSetInfo",
+)
+
+visibility([
+    "//cc/toolchains/...",
+    "//tests/rule_based_toolchain/...",
+])
+
+def _cc_external_feature_impl(ctx):
+    feature = FeatureInfo(
+        label = ctx.label,
+        name = ctx.attr.feature_name,
+        enabled = False,
+        args = ArgsListInfo(
+            label = ctx.label,
+            args = (),
+            files = depset([]),
+            by_action = (),
+        ),
+        implies = depset([]),
+        requires_any_of = (),
+        mutually_exclusive = (),
+        external = True,
+        overridable = ctx.attr.overridable,
+        overrides = None,
+    )
+    providers = [
+        feature,
+        FeatureSetInfo(label = ctx.label, features = depset([feature])),
+        FeatureConstraintInfo(
+            label = ctx.label,
+            all_of = depset([feature]),
+            none_of = depset([]),
+        ),
+    ]
+    return providers
+
+cc_external_feature = rule(
+    implementation = _cc_external_feature_impl,
+    attrs = {
+        "feature_name": attr.string(
+            mandatory = True,
+            doc = "The name of the feature",
+        ),
+        "overridable": attr.bool(
+            doc = "Whether the feature can be overridden",
+            mandatory = True,
+        ),
+    },
+    provides = [FeatureInfo, FeatureSetInfo, FeatureConstraintInfo],
+    doc = "A declaration that a feature with this name is defined elsewhere.",
+)
diff --git a/tests/rule_based_toolchain/features/BUILD b/tests/rule_based_toolchain/features/BUILD
index 701d478..2d0dce7 100644
--- a/tests/rule_based_toolchain/features/BUILD
+++ b/tests/rule_based_toolchain/features/BUILD
@@ -3,6 +3,7 @@ load("//cc/toolchains:args.bzl", "cc_args")
 load("//cc/toolchains:feature.bzl", "cc_feature")
 load("//cc/toolchains:feature_constraint.bzl", "cc_feature_constraint")
 load("//cc/toolchains:feature_set.bzl", "cc_feature_set")
+load("//cc/toolchains/impl:external_feature.bzl", "cc_external_feature")
 load("//tests/rule_based_toolchain:analysis_test_suite.bzl", "analysis_test_suite")
 load(":features_test.bzl", "TARGETS", "TESTS")
 
@@ -84,6 +85,21 @@ util.helper_target(
     none_of = [":implies"],
 )
 
+util.helper_target(
+    cc_external_feature,
+    name = "builtin_feature",
+    feature_name = "builtin_feature",
+    overridable = True,
+)
+
+util.helper_target(
+    cc_feature,
+    name = "overrides",
+    args = [":c_compile"],
+    enabled = True,
+    overrides = ":builtin_feature",
+)
+
 analysis_test_suite(
     name = "test_suite",
     targets = TARGETS,
diff --git a/tests/rule_based_toolchain/features/features_test.bzl b/tests/rule_based_toolchain/features/features_test.bzl
index b6a7db6..3406bdd 100644
--- a/tests/rule_based_toolchain/features/features_test.bzl
+++ b/tests/rule_based_toolchain/features/features_test.bzl
@@ -93,6 +93,16 @@ def _feature_constraint_collects_transitive_features_test(env, targets):
         targets.implies.label,
     ])
 
+def _external_feature_is_a_feature_test(env, targets):
+    env.expect.that_target(targets.builtin_feature).provider(
+        FeatureInfo,
+    ).name().equals("builtin_feature")
+
+def _feature_can_be_overridden_test(env, targets):
+    overrides = env.expect.that_target(targets.overrides).provider(FeatureInfo)
+    overrides.name().equals("builtin_feature")
+    overrides.overrides().some().label().equals(targets.builtin_feature.label)
+
 TARGETS = [
     ":c_compile",
     ":simple",
@@ -103,6 +113,8 @@ TARGETS = [
     ":mutual_exclusion_feature",
     ":direct_constraint",
     ":transitive_constraint",
+    ":builtin_feature",
+    ":overrides",
 ]
 
 # @unsorted-dict-items
@@ -114,4 +126,6 @@ TESTS = {
     "feature_set_collects_features_test": _feature_set_collects_features_test,
     "feature_constraint_collects_direct_features_test": _feature_constraint_collects_direct_features_test,
     "feature_constraint_collects_transitive_features_test": _feature_constraint_collects_transitive_features_test,
+    "external_feature_is_a_feature_test": _external_feature_is_a_feature_test,
+    "feature_can_be_overridden_test": _feature_can_be_overridden_test,
 }