diff --git a/changelog/fix_restore_rubocop_config_loader_project_root.md b/changelog/fix_restore_rubocop_config_loader_project_root.md
new file mode 100644
index 00000000000..d6842c48d6c
--- /dev/null
+++ b/changelog/fix_restore_rubocop_config_loader_project_root.md
@@ -0,0 +1 @@
+* [#10871](https://github.com/rubocop/rubocop/issues/10871): Restore `RuboCop::ConfigLoader.project_root` as deprecated. ([@koic][])
diff --git a/lib/rubocop/config_loader.rb b/lib/rubocop/config_loader.rb
index 6bbcdcf3b16..f594843f52a 100644
--- a/lib/rubocop/config_loader.rb
+++ b/lib/rubocop/config_loader.rb
@@ -137,6 +137,18 @@ def default_configuration
         end
       end
 
+      # Returns the path RuboCop inferred as the root of the project. No file
+      # searches will go past this directory.
+      # @deprecated Use `RuboCop::ConfigFinder.project_root` instead.
+      def project_root
+        warn Rainbow(<<~WARNING).yellow
+          `RuboCop::ConfigLoader.project_root` is deprecated and will be removed in RuboCop 2.0. \
+          Use `RuboCop::ConfigFinder.project_root` instead.
+        WARNING
+
+        ConfigFinder.project_root
+      end
+
       PENDING_BANNER = <<~BANNER
         The following cops were added to RuboCop, but are not configured. Please set Enabled to either `true` or `false` in your `.rubocop.yml` file.