The Rance is a 79 miles (127 km) long Breton coastal river that rises in the Mené mountains in Collinée (Côtes-d'Armor) and flows into the English Channel between Dinard and Saint-Malo (Ille-et-Vilaine). Blocked near its mouth by the lock dam of a tidal power plant, the Rance forms a wide basin with banks lined with bays and small river ports such as Le Minihic-sur-Rance (photo). Its estuary is 750 metres wide at its mouth and covers an area of 13.6 sq. miles (22 km²). The rising tide can be felt as far as the Châtelier lock at Saint-Samson-sur-Rance, located some 12 miles (20 km) upstream. The Rance river reveals vast open areas at low tide.