Athabasca

River and lake in Alberta and Saskatchewan, Canada. The river, a tributary of the Mackenzie, is 1,230 km/764 mi long. Its source is a small lake at the base of Mount Brown in the Rocky Mountains, called the Committee's Punchbowl. The river flows northeast across Alberta where it enters Lake Athabasca, the fourth-largest lake entirely within Canada (length 320 km/199 mi; area 7,936 sq km/3,064 sq mi). Large tar-sand deposits (source of the hydrocarbon mixture ‘heavy oil’) have been found to the southwest of the lake, near Fort McMurray. They were not exploited until technology was developed that could extract the oil from the sand at reasonable cost. Reserves are estimated at 1.7 trillion barrels of oil, of which about 300 billion are recoverable with modern technology.

The Athabasca River was an important route for the fur trade, and Fort Chipewyan (1788), on the western edge of Lake Athabasca, was one of the centres of trade. Commercial fishing is now practised on Lake Athabasca.

The Oil Sands Discovery Centre opened near Fort McMurray in 1985.