Flathead Lake is the largest freshwater lake in Montana, located in the town of Polson. The lake was formed by glaciers during the last ice age and has a surface area of 191.5 square miles. Its hydrology is dominated by the Flathead River, which is the primary surface flow provider, and snowpack, which provides the majority of the lake's water. The lake serves as a vital source of irrigation water for local agriculture and supports a variety of recreational activities, including fishing, boating, and swimming. The lake is also home to several species of fish, including trout, salmon, and bass. Its history includes being a sacred site for the Salish and Kootenai tribes and being explored by Lewis and Clark in 1805. Today, Flathead Lake is considered one of Montana's most treasured natural resources.