Lake, south-central Northwest Territories, Canada. Named for the Slave Indians, it is fed by several rivers, including the Slave, and drained by the Mackenzie River into the Arctic Ocean. The lake, with an area of 11,031 sq mi (28,570 sq km), is the fifth largest in North America. It is 300 mi (500 km) long and 30–140 mi (50–225 km) wide, with a maximum depth of more than 2,000 ft (600 m). While supporting a fishing industry, the lake is an integral part of the Mackenzie River waterway.