The Rance (; , ) is a river of northwestern France. It is long. The semi-tidal river flows into the English Channel between Dinard and Saint-Malo.
Before reaching the Channel, its waters are barred by a 750 metre long dam forming the Rance tidal power plant.
The river is linked to the Vilaine by means of the Canal d'Ille-et-Rance.
Départements and towns along the river:
- Côtes-d'Armor: Collinée, Caulnes, Dinan
- Ille-et-Vilaine: Dinard, Saint-Malo
Hydrology and water quality
Tributaries of the Rance include:
- Croqueloir
- Clergé
- Fremeur
- Quinéford
This river has moderate turbidity and its brownish water is somewhat low in velocity due to the slight gradient of the watercourse; pH levels have been measured at 8.13 within the city of Dinan and electrical conductivity of the waters have tested at 33 micro-siemens per centimetre. At this reference location, summer flows are typically in the range of .