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
Mackenzie River with sternwheelers transporting passengers, domestic supplies and industrial goods from as far upstream as the Athabasca River all the way to the delta, though with several areas such as the huge rapids on the Slave River requiring portages. The route taken by gold seekers started in Edmonton and followed the Athabasca, Slave and Mackenzie Rivers as far as the Peel River, then up the Peel and its tributary the Rat River to the headwaters of the Porcupine River, which flows to the Yukon River. Many who attempted the journey died along the way or turned back before reaching the Yukon.