diff --git a/actionpack/lib/action_dispatch/railtie.rb b/actionpack/lib/action_dispatch/railtie.rb
index c66e2744d4..18d3a7d317 100644
--- a/actionpack/lib/action_dispatch/railtie.rb
+++ b/actionpack/lib/action_dispatch/railtie.rb
@@ -68,8 +68,6 @@ class Railtie < Rails::Railtie # :nodoc:
       config.action_dispatch.always_write_cookie = Rails.env.development? if config.action_dispatch.always_write_cookie.nil?
       ActionDispatch::Cookies::CookieJar.always_write_cookie = config.action_dispatch.always_write_cookie
 
-      ActionDispatch::Routing::Mapper.route_source_locations = Rails.env.development?
-
       ActionDispatch::Http::Cache::Request.strict_freshness = app.config.action_dispatch.strict_freshness
       ActionDispatch.test_app = app
     end
diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index 8701806419..3a6cc8e3f1 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -6,6 +6,7 @@
 require "active_support/core_ext/enumerable"
 require "active_support/core_ext/array/extract_options"
 require "active_support/core_ext/regexp"
+require "action_dispatch/routing"
 require "action_dispatch/routing/redirection"
 require "action_dispatch/routing/endpoint"
 
diff --git a/railties/CHANGELOG.md b/railties/CHANGELOG.md
index 9b7504cb07..cb5afb68c5 100644
--- a/railties/CHANGELOG.md
+++ b/railties/CHANGELOG.md
@@ -1,3 +1,8 @@
+*   Enable tracking route source locations only when using routes command. Previously,
+    it was enabled in development mode, but is only needed for `bin/rails routes -E`.
+
+    *Gannon McGibbon*
+
 *   Deprecate `bin/rake stats` in favor of `bin/rails stats`.
 
     *Juan Vásquez*
diff --git a/railties/lib/rails/commands/routes/routes_command.rb b/railties/lib/rails/commands/routes/routes_command.rb
index c979a9014b..a19a653bd1 100644
--- a/railties/lib/rails/commands/routes/routes_command.rb
+++ b/railties/lib/rails/commands/routes/routes_command.rb
@@ -22,6 +22,8 @@ def invoke_command(*)
 
       desc "routes", "List all the defined routes"
       def perform(*)
+        require "action_dispatch/routing/mapper"
+        ActionDispatch::Routing::Mapper.route_source_locations = true
         boot_application!
         require "action_dispatch/routing/inspector"
 
diff --git a/railties/test/commands/routes_test.rb b/railties/test/commands/routes_test.rb
index 58ccad1516..74a9dfadee 100644
--- a/railties/test/commands/routes_test.rb
+++ b/railties/test/commands/routes_test.rb
@@ -403,6 +403,12 @@ class Rails::Command::RoutesTest < ActiveSupport::TestCase
     assert_includes(output, "No unused routes found.")
   end
 
+  test "route source locations aren't included when booted normally" do
+    output = rails "runner", "print !!ActionDispatch::Routing::Mapper.route_source_locations"
+
+    assert_equal("false", output)
+  end
+
   private
     def run_routes_command(args = [])
       rails "routes", args