Athabasca River is marked by rapids, impeding navigation southwest of Fort McMurray. The Athabasca River travels before draining into the Peace-Athabasca Delta near Lake Athabasca south of Fort Chipewyan. From there, its waters flow north as Rivière des Rochers, then joining the Peace River to form the Slave River that empties into Great Slave Lake and discharges through the Mackenzie River system into the Arctic Ocean. The cumulative drainage area is . Numerous communities are located on the banks of the Athabasca River, including Jasper, Brule, Entrance, Hinton, Whitecourt, Fort Assiniboine, Smith, Athabasca, Fort McMurray, and Fort McKay. An independent study has
Lake Huron as two 'lobes of the same lake'). Aggregated, Lake Huron-Michigan, at , "is technically the world's largest freshwater lake." When counted separately, Lake Superior is larger than Huron and higher. Lake Superior drains into the St. Marys River which then flows southward into Lake Huron. The water then flows south to the St. Clair River, at Port Huron, Michigan and Sarnia, Ontario. The Great Lakes Waterway continues thence to Lake St. Clair; the Detroit River and Detroit, Michigan; into Lake Erie and thence – via Lake Ontario and the St. Lawrence River – to the Atlantic Ocean. Like the other