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.
List of longest rivers of Canada
The primary source for data in the table below is "The Atlas of Canada"; other sources are as noted. Discharge refers to the flow at the mouth except as noted. U.S. states appear in italics. Abbreviations are as follows: "km" for "kilometre", "mi" for "mile", "s" for "second", "m" for "metre", and "ft" for "foot".