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
Mackenzie River with sternwheelers transporting passengers, domestic supplies and industrial goods from as far upstream as the Athabasca River all the way to the delta, though with several areas such as the huge rapids on the Slave River requiring portages. The route taken by gold seekers started in Edmonton and followed the Athabasca, Slave and Mackenzie Rivers as far as the Peel River, then up the Peel and its tributary the Rat River to the headwaters of the Porcupine River, which flows to the Yukon River. Many who attempted the journey died along the way or turned back before reaching the Yukon.