diff --git a/config/routes.rb b/config/routes.rb
index 8723cfd6..c3ab9f98 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -15,9 +15,14 @@
 
   resources :settings, only: %i[create]
 
-  get ':section', to: 'pages#index'
-  get ':section/:slug', to: 'pages#show'
-  get ':section/:overview/:slug', to: 'pages#show'
+  get ':section', to: 'pages#index', format: 'html'
+  get ':section/:slug', to: 'pages#show', format: 'html'
+  get ':section/:overview/:slug', to: 'pages#show', format: 'html'
+
+  # Handle unmatched route
+  get '/*unmatched_route', to: 'errors#not_found', via: :get, format: 'html'
+  get '/*unmatched_route/*unmatched_route', to: 'errors#not_found', via: :get, format: 'html'
+  get '/*unmatched_route/*unmatched_route/*unmatched_route', to: 'errors#not_found', via: :get, format: 'html'
 
   post 'change', to: 'hook#change'
   post 'release', to: 'hook#release'
diff --git a/spec/system/page_tier_spec.rb b/spec/system/page_tier_spec.rb
index fec4be0e..602c06ad 100644
--- a/spec/system/page_tier_spec.rb
+++ b/spec/system/page_tier_spec.rb
@@ -109,4 +109,34 @@
       end
     end
   end
+
+  describe 'First tier when route is in incorrect format' do
+    before do
+      visit '/randompage.yml'
+    end
+
+    it 'has a heading' do
+      expect(page).to have_text('Page not found')
+    end
+  end
+
+  describe 'Second tier when route is in incorrect format' do
+    before do
+      visit '/route/randompage.yml'
+    end
+
+    it 'has a heading' do
+      expect(page).to have_text('Page not found')
+    end
+  end
+
+  describe 'Third tier when route is in incorrect format' do
+    before do
+      visit '/route/route/randompage.yml'
+    end
+
+    it 'has a heading' do
+      expect(page).to have_text('Page not found')
+    end
+  end
 end