Kösen is a lake southwest of Ljungby in Ljungby, Kronoberg. The lake is located along the Lagan River flowing in from the west of Bolmen and flows south towards Exen and Lagan. Sea area is 11.75 square kilometers and the maximum depth of 22 meters.
Kösen offers good fishing of several species. Inter alia Walleye, pike, perch, trout, bream, roach, eel and tench.