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
Churchill River (Hudson Bay) and the rest flows as the Churchill River into Hudson Bay at Churchill, Manitoba. (see also Nelson River Hydroelectric Project) The Churchill formed a major part of the "voyageur highway" in the 18th to 20th centuries after Dene people showed Peter Pond the Methye Portage which connects the Hudson Bay watershed with the Clearwater – Athabasca – MacKenzie rivers which flow to the Arctic Ocean. See Canadian Canoe Routes (early). The Churchill is also home of several fish species including: walleye, sauger, yellow perch, northern pike, lake trout, lake whitefish, cisco, white sucker, shorthead redhorse, longnose sucker, lake sturgeon and