Image of Flathead Lake

-- Scenic view of a white tailed deer standing in front of Flathead Lake outside of Polson, Montana - June 2006 Flathead Lake is the largest natural freshwater lake in the western United States. Lying in the Flathead Valley of Northwest Montana, the lake is more then 300 feet deep and extends north and south some 28 miles and is seven to 15 miles wide. The focus is clear from the foreground vegetation to the distant Rocky Mountains.