diff --git a/config/routes.rb b/config/routes.rb
index 867980bc1..261491519 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -1,3 +1,4 @@
+# For details on the DSL available within this file, see https://guides.rubyonrails.org/routing.html
 Rails.application.routes.draw do
   devise_for :admin_users, {
     path: :admin,
@@ -28,12 +29,10 @@ Rails.application.routes.draw do
 
   get "/health", to: ->(_) { [204, {}, [nil]] }
 
-  # For details on the DSL available within this file, see https://guides.rubyonrails.org/routing.html
   ActiveAdmin.routes(self)
 
   root to: "start#index"
 
-  # Content pages
   get "/accessibility-statement", to: "content#accessibility_statement"
   get "/privacy-notice", to: "content#privacy_notice"
 
diff --git a/spec/config/routes_spec.rb b/spec/config/routes_spec.rb
new file mode 100644
index 000000000..e5f0505f4
--- /dev/null
+++ b/spec/config/routes_spec.rb
@@ -0,0 +1,23 @@
+require "rails_helper"
+
+RSpec.describe "routes.rb" do
+  let(:all_routes) do
+    Rails.application.routes.routes.map { |r| r.path.spec.to_s if r.defaults[:controller] }.compact
+  end
+  let(:active_admin_routes_prefix) { "/admin" }
+  let(:rails_routes_prefix) { "/rails" }
+  let(:turbo_routes_pattern) { "_historical_location" }
+  let(:project_routes) do
+    all_routes.reject do |r|
+      r.starts_with?(active_admin_routes_prefix) || r.starts_with?(rails_routes_prefix) ||
+        r.include?(turbo_routes_pattern)
+    end
+  end
+
+  it "does not use underscores" do
+    routes_with_underscores = project_routes.select do |r|
+      r.split("/").any? { |component| !component.start_with?(":") && component.match("_") }
+    end
+    expect(routes_with_underscores).to be_empty
+  end
+end