Mackenzie River
At , the Mackenzie River drainage basin encompasses nearly 20 percent of Canada. About , or 54 percent of the basin, lies above Great Slave Lake. Permafrost underlies about three-quarters of the watershed, reaching up to deep in the Mackenzie Delta. As a whole, the Mackenzie basin receives only meager to moderate rainfall, averaging over the entire basin, though mountain areas experience much higher precipitation, and areas near and north of the Arctic Circle receive much lower precipitation.
Canadian Rockies
The Canadian Rockies are noted for being the source of several major river systems, and also for the many rivers within the range itself. The Rockies form the divide between the Pacific Ocean drainage on the west and that of Hudson Bay and the Arctic Ocean on the east. Of the range's rivers, only the Peace River penetrates the range. Notable rivers originating in the Canadian Rockies include the Fraser, Columbia, North Saskatchewan, Bow and Athabasca Rivers.