river, rising in the Landes du Mené, a chain of hills in Côtes-d'Armor département, Brittany région, western France. It flows for 60 miles (97 km) past Dinan to form an estuary on the Brittany coast of the English Channel at Saint-Malo, where the world's first large-scale tidal plant, using flood and ebb tides to generate electricity, was completed in 1967.