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
Besa River Granger Creek also flows in the Besa River west of Klingzut Mountain. Shortly after, Besa River flows into the Prophet River as a right tributary, at an elevation of . Its waters are carried via the Prophet River, Muskwa River, Fort Nelson River, Liard River and Mackenzie River, ultimately into the Arctic Ocean. Besa River Besa River is a river in northern British Columbia, Canada. It is a tributary of the Prophet River. The river flows through the Muskwa Ranges, and is the backbone of the Redfern-Keily Provincial Park, part of the larger Muskwa-Kechika Management Area. It gives the name