Fjergen is a lake in Meråker Municipality in Trøndelag county, Norway. The 14.41-square-kilometre (5.56 sq mi) lake has a hydropower dam on the southern end which flows out into the Kåpperåa river which is part of the Stjørdalselva river system. There is about 204,000,000 cubic metres (7.2×109 cu ft) of water stored in the lake.