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
Turnagain River Turnagain River The Turnagain River is a river in the Canadian province of British Columbia. The Turnagain River was named by Samuel Black of the Hudson's Bay Company, who in 1824 journeyed to the river before turning back. Part of the river flows through the Muskwa-Kechika Management Area. The Turnagain River flows generally east and north to join the Kechika River. The Kechika River is a tributary of the Liard River, which is in turn tributary to the Mackenzie River, which empties into the Arctic Ocean. A notable tributary is the Cassiar River, which flows north to joins the Turnagain