Swan Lake is a lake located east of Flathead Lake and the town of Bigfork, Montana. The Swan River comes from the south and fills the lake. The lake is similar to Moyie Lake in southern British Columbia. It is a narrow, small, and twisty lake that is hard to navigate. There is a small divide that separates the Swan River Valley from the Clearwater River Valley. T…Swan Lake is a lake located east of Flathead Lake and the town of Bigfork, Montana. The Swan River comes from the south and fills the lake. The lake is similar to Moyie Lake in southern British Columbia. It is a narrow, small, and twisty lake that is hard to navigate. There is a small divide that separates the Swan River Valley from the Clearwater River Valley. The Clearwater River flows south through a series of lakes, including Seeley Lake and empties into the Blackfoot River. The two valleys are known locally as the Seeley/Swan. Swan Lake runs parallel to Montana Highway 83.