The routes from Evreux to Beauvais and Paris to Rouen by the Seine put Vernon on the border between Normandy and Île-de-France. Its motto, Vernon semper viret (Vernon always green), highlights the rich biodiversity of its environment. Vernon's right and left banks have been listed as historical sites since the 1940s due to their significant architectural heritage. Nearby, the caves of Mont Roberge house underground cavities dug in Cretaceous chalk. They are protected by the Natura 2000 network as they are home to bats such as the lesser horseshoe bat, unique in Normandy.