The southern portion of the route is part of the Banff-Windermere Highway, a highway that travels from British Columbia Highway 95 at Radium Hot Springs, through Kootenay National Park and Vermilion Pass across the Continental Divide, to the junction of the Trans-Canada Highway (Highway 1) at Castle Junction. The final of the highway are in Alberta and Banff National Park. Prior to 1959, the highway was designated as Highway 1B.