List of longest rivers of Canada
Nine rivers in this list cross international boundaries or form them. Four—the Yukon, Columbia, Porcupine, and Kootenay—begin in Canada and flow into the United States. Five—the Milk, Pend d'Oreille, Saint Lawrence, Red, and Saint John—begin in the United States and flow into Canada. Of these, the Milk and the Kootenay cross the international border twice, the Milk leaving and then re-entering the United States, the Kootenay leaving and then re-entering Canada. The drainage basins of these nine rivers extend into both countries; in addition, the drainage basins of six others—the Fraser, Assiniboine, South Saskatchewan, Saskatchewan, Nelson, and Winnipeg—extend into the United States even though their main stems flow entirely within Canada.
Canadian Rockies
The Canadian Rockies are noted for being the source of several major river systems, and also for the many rivers within the range itself. The Rockies form the divide between the Pacific Ocean drainage on the west and that of Hudson Bay and the Arctic Ocean on the east. Of the range's rivers, only the Peace River penetrates the range. Notable rivers originating in the Canadian Rockies include the Fraser, Columbia, North Saskatchewan, Bow and Athabasca Rivers.