Fjergen is a lake in the municipality of Meråker in Trøndelag county, Norway. The 14.41 km2 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 m3 of water stored in the lake. The lake is located about 5 km north of the village of Kopperå and about 7 km northeast of the municipal center of Midtbygda. The lakes Feren and Funnsjøen lie several kilometers to the northwest, and the border with Sweden lies a few kilometers to the east.