Lake Guerlédan (French pronunciation: [ɡɛʁledɑ̃]) is an artificial lake in the centre of Brittany, France. It extends across the borders of the departments of Morbihan and Côtes-dArmor, within the communes of Saint-Aignan, Morbihan and Mûr-de-Bretagne. At an elevation of 121 m, its surface area is 4 km2. Lake Guerlédan is the largest artificial lake in Brittany.
