| name | image | Average flow (m³/s) | basin (m²) | Height (m) | origin location | mouth location | Length (m) | latitude (°) | longitude (°) | canyon | Map |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Ille |  | 470,000,000 | 66 | Vilaine | 47,000 | 48.1081000000 | -1.6974000000 | Map | |||
| L'Isac |  | 658,000,000 | Vilaine | 69,300 | 47.5780555600 | -2.1019444400 | Map | ||||
| Meu |  | 468,000,000 | 225 | Vilaine | 84,800 | 48.0322222200 | -1.7766666700 | Map | |||
| Oust |  | 27 | 3,630,000,128 | 225 | Le Haut-Corlay | Vilaine | 137,000 | 47.6315000000 | -2.0972000000 | Map | |
| Seiche |  | 820,000,000 | 167 | Vilaine | 97,300 | 47.9972000000 | -1.7554000000 | Map |