Harrsjøen is a lake in Rendalen Municipality in Innlandet county, Norway. The 2.31-square-kilometre (0.89 sq mi) lake lies about 3 kilometres (1.9 mi) southwest of the village of Bergset and about 8 kilometres (5.0 mi) northeast of the village of Hanestad. The lake has an outlet in the south through the river Hårenna, a tributary of the river Renaelva.[1]