Mackenzie River

The Mackenzie River is the longest river system in Canada, and has the second largest drainage basin of any North American river after the Mississippi River. The Mackenzie River flows through a vast, thinly populated region of forest and tundra entirely within the Canadian Northwest Territories, although its many tributaries reach into four other Canadian provinces and territories.

The river's main stem is 1,738 kilometres long, flowing north-northwest from Great Slave Lake into the Arctic Ocean, where it forms a large delta at its mouth. Its extensive watershed drains about 20 percent of Canada. It is the largest river flowing into the Arctic from North America, and including its tributaries has a total length of 4,241 kilometres, making it the thirteenth longest river system in the world.