The Lac de Saint-Cassien (Lake of Saint-Cassien) is a reservoir in the Var department, Southern France, not far from the border with Alpes-Maritimes. It is bordered by Montauroux, Tanneron and Les Adrets-de-l'Estérel. At an elevation of 147 m (482 ft), its surface area is 4.2 km2 (1.6 sq mi). The EDF Barrage de Saint-Cassien (Saint-Cassien Dam), northeast of the lake in the commune of Tanneron, was put into service in 1966. Both the dam and reservoir were named after John Cassian (Jean Cassien), a Christian saint who founded the Abbey of St Victor in Marseille.