Colliford Lake is a reservoir on Bodmin Moor, Cornwall, England, United Kingdom. Covering more than 900 acres (3.6 km2), it is the largest lake in Cornwall. It is situated south of the A30 trunk road near the village of Bolventor, the approximate centre of the lake being at OS grid reference SX179730. Dozmary Pool outfallis into the lake and the lake's own outfall forms one of the tributaries of the River Fowey.