river in the län (counties) of Västerbotten and Västernorrland, northern Sweden. It rises in Swedish Lapland near the Norwegian border and flows in a winding course for 285 miles (460 km) southeast past Vilhelmina, Åsele, Sollefteå, and Kramfors, emptying into the Gulf of Bothnia a few miles northeast of Härnösand. The Fjällsjö and Fax rivers are its main tributaries. In the plateau region are Lake Vojm and Lake Flå, both of which help to regulate the river flow. Because of the many falls along the river's route, hydroelectric power stations are numerous. Lumber and pulp mills are found along the river's 20-mile- (32-km-) long navigable estuary. It has a drainage area of 12,302 square miles (31,865 square km).