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 in the Canadian Rockies, Crowsnest River meanders eastward through the Municipality of Crowsnest Pass and Frank Slide. It passes into the foothills near Burmis and reaches the western margiā¦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 in the Canadian Rockies, Crowsnest River meanders eastward through the Municipality of Crowsnest Pass and 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.