Great Slave Lake, second largest lake of Canada, c.10,980 sq mi (28,400 sq km), Northwest Territories, named for the Slave (Dogrib), a tribe of Native Americans. It is c.300 mi (480 km) long and from 12 to 68 mi (19–109 km) wide and is the deepest lake (2,015 ft/614 m) of North America. The Hay and Slave rivers are its chief tributaries; it is drained by the Mackenzie River. The western shores are wooded, but the long east and north arms reach into tundralike country. Samuel Hearne, a British fur trader, explored the lake in 1771. Gold was discovered in the 1930s on the northern shore, and the town of Yellowknife was established as a mining center. The area is still important for gold mining. The lake has commercial fisheries. Fort Providence, Hay River, and Fort Resolution are the chief towns on the lake.