The Crowsnest River is a tributary to the Oldman River in southwestern Alberta, Canada.
From its source in Crowsnest Lake at an elevation of about 1,357 metres (4,452 ft) in the Canadian Rockies, it meanders eastward through the Municipality of Crowsnest Pass and the Frank Slide. It passes into the foothills near Burmis and reaches the western margin of the Alberta plains near Lundbreck. It then joins the Oldman River Reservoir at an elevation of about 1,110 metres (3,640 ft).
The Crowsnest River is a highly productive river with a substantial insect population that fuels a world-class sport fishery for rainbow, westslope cutthroat, bull, hybrid trout ("cutbow" cutthroat and rainbow trout crosses), and brown trout (below Lundbreck Falls), mountain whitefish, and various species of suckers.
Coordinates: 49°35′59″N 114°02′57″W / 49.59972°N 114.04917°W