Kopseng is a village in Sigdal Municipality, in Buskerud, Norway. Kopseng lies at 387 m above sea level, at the foot of the Norefjell mountains. The nearest city is Kongsberg, 59 km to the southeast. Among the landmarks around are Nore Stave Church (21 km), Rollag Stave Church (19.1 km) and Uvdal Stave Church (32 km).