Athabasca, Lake

Athabasca, Lake, lake in western Canada, straddling the borders of Alberta and Saskatchewan. It is about 320 km (200 mi) long and covers about 7,936 sq km (3,064 sq mi). Fort Chipewyan, which was built along the south-western shore of the lake in 1788 by the North West Company, became one of the region's most important fur-trading posts. Today Lake Athabasca is used for commercial fishing. It is fed to the south-west by the Athabasca River, and drained to the north by the Slave River. The area around the delta of the Athabasca River contains large deposits of oil in the form of tar sands. Uranium has been mined on the north coast since the 1950s.