Oust

For the commune in southern France, see Oust, Ariège.

The Oust (French pronunciation: [ust]; Breton: Oud) is a river in Brittany, France, right tributary of the Vilaine. It is 145 km (90 mi) long.^[1] Its source is in the hills between Corlay and Quintin. It flows generally southeast, through the following départements and towns:

• Côtes-d'Armor: Uzel
• Morbihan: Rohan, Josselin, Malestroit
• Ille-et-Vilaine: Redon

Oust
Oust river in Josselin
Location
Country	France
Physical characteristics
Source
• location	Brittany
Mouth
• location	Vilaine
• coordinates	47°37′50″N 2°5′49″W
Length	145 km (90 mi)
Basin size	3,630 km2 (1,400 sq mi)
Discharge
• average	25 m3/s (880 cu ft/s)
Basin features
Progression	Vilaine→ Atlantic Ocean

The Oust flows into the river Vilaine in Redon. The part of the Oust between Rohan and Redon has been made navigable for small ships, and forms part of the Canal de Nantes à Brest.

The rivers Aff, Arz and Ninian are among its tributaries.