Mackenzie River Mackenzie River The Mackenzie River (Slavey language: Deh-Cho , "big river" or Inuvialuktun: Kuukpak , "great 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 long, flowing north-northwest from Great Slave Lake into the Arctic Ocean, where it forms a large delta at its mouth. Its extensive
Rapid River (Cree River tributary) flow via the Cree River, the Fond du Lac River and the Mackenzie River to the Arctic Ocean. Rapid River (Cree River tributary) The Rapid River is a river in northern Saskatchewan, Canada. It is part of the Mackenzie River drainage basin. The Rapid River begins at an unnamed lake at an elevation of . It travels north to Kirsch Lake at an elevation of , where it takes in several unnamed tributaries, including one from the left arriving from Halliday Lake. The river continues to Parker Lake at an elevation of where it takes in the left tributary Arnold