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
Petitot River Dene language of the Slavey First Nations is "mbehcholah", "The Black". It has a total length of and a drainage area of . Petitot River Petitot is a river in northern Alberta and British Columbia, Canada. It is a tributary of the Liard River. Petitot River originates from Bistcho Lake in northwestern Alberta, and flows westwards along the northern borders of Alberta and British Columbia. It then passes in the Northwest Territories, where it discharges in the Liard River at the village of Fort Liard. From there, its waters are carried to the Arctic Ocean through the Mackenzie River. The