Mackenzie

Mackenzie, river in the Inuvik and Fort Smith regions of the Northwest Territories, north-western Canada, about 1,705 km (1,060 mi) long. The Mackenzie rises in Great Slave Lake and flows north-west before emptying through a large delta into Mackenzie Bay, an arm of the Beaufort Sea. In all this distance the total fall of the river is only 156 m (512 ft), so it is wide for most of its course, averaging a width of 3.2 km (2 mi). It is navigable from June to October, when it freezes over. The Mackenzie Valley, between the Mackenzie Mountains and the Canadian Shield, is sparsely populated and has few economic resources, although petroleum is produced near Norman Wells and oil and natural gas have been found in the delta region. Muskrat-trapping is also important in the delta region. The Mackenzie is part of the longest river system in Canada, 4,241 km (2,635 mi) long—second only to the Missouri-Mississippi system in North America. Its drainage basin covers a total of 1.8 million sq km (700,000 sq mi). The average discharge at its mouth is 9.6 million litres (2.1 million gallons) per second. The river was explored in 1789 by Sir Alexander Mackenzie, after whom it is named. Steamers operated on the river from the 1880s until the 1940s.