Mackenzie River east into the Churchill River. The eastern portion of the Mackenzie basin is dominated by vast reaches of lake-studded boreal forest and includes many of the largest lakes in North America. By both volume and surface area, Great Bear Lake is the biggest in the watershed and third largest on the continent, with a surface area of and a volume of . Great Slave Lake is slightly smaller, with an area of and containing of water, although it is significantly deeper than Great Bear. The third major lake, Athabasca, is less than a third that size with an area of
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