Alberta Provincial Highway No. 1, commonly referred to as Highway 1, is a major east–west highway in southern Alberta that forms the southern mainline of the Trans-Canada Highway. It runs from the British Columbia border near Lake Louise through Calgary to the Saskatchewan border east of Medicine Hat. It continues as Highway 1 into both provinces. It spans approximately 534 km (332 mi) from Alberta's border with British Columbia in the west to its border with Saskatchewan in the east. Highway 1 is designated as a core route in Canada's National Highway System and is a core part of the developing Alberta Freeway Network.

The Trans-Canada Highway is a transcontinental federal–provincial highway system that travels through all ten provinces of Canada, from the Pacific Ocean on the west coast to the Atlantic Ocean on the east coast. The main route spans 7,476 km (4,645 mi) across the country, one of the longest routes of its type in the world. The highway system is recognizable by its distinctive white-on-green maple leaf route markers, although there are small variations in the markers in some provinces.