Athabasca River

River in northern Alberta, Canada, forming the southernmost part of the Mackenzie River system. From its source in the Columbia Icefield (Canadian Rocky Mountains) near the Continental Divide, the river flows through Jasper National Park, site of the spectacular Athabasca Falls, northeastward across Alberta to its mouth and delta on Lake Athabasca. Its 765-mi (1,231-km) course