The Athabasca River is the longest river in Alberta (1,538 km). The first 168 km (located in Jasper National Park) are designated as a Canadian Heritage River. As a tributary to the Mackenzie River, water flowing on the Athabasca River eventually drains into the Arctic Ocean. River flow is highest during the summer and lowest during winter, and it is ice-covered from mid-November to mid-April.
These 2 great journeys were first made just before the end of the 18th century, and by the same man. Alexander Mackenzie reached the mouth of the river which now bears his name in 1789, and was the first European to cross the North American continent (to Bella Coola) in 1793.
It is virtually landlocked but is joined to the Arctic Ocean to the north by Foxe Channel and Fury and Hecla Strait, and to the Atlantic Ocean on the east by Hudson Strait. Baffin Island lies athwart the entrance to the bay, and Southampton, Coats and Mansel islands are lodged across the northern gap.