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
Fond du Lac River (Saskatchewan) Fond du Lac River (Saskatchewan) The Fond du Lac River is one of the upper branches of the Mackenzie River system, draining into the Arctic Ocean, located in northern Saskatchewan, Canada. The river is long, has a watershed of , and its mean discharge is . The river begins at an elevation of at Cunning Bay on Wollaston Lake. It flows north to Hatchet Lake at an elevation of and continues to Waterfound Bay at an elevation of , where the tributary Waterfound River enters from the left. The river continues north to Kosdaw Lake at an elevation of ,