Trogtal
Numedal is the southernmost valley of the major valleys in Eastern Norway. Numedal is largely a U-shaped valley. Most of the area is mountainous, especially west of the main valley, with steep valley sides. Running north–south, it extends between Flesberg in the south to Rødberg in the north, passing through the municipalities of Flesberg, Rollag and Nore og Uvdal. The Numedalslågen, the third-longest river in Norway, flows through the valley before discharging into Oslofjord at Larvik.