Flathead Lake

Flathead Lake from the west side looking across Wild Horse Island to the Missions

Flathead Lake from the west side looking across Wild Horse Island to the Missions

Glaciers scoured the Flathead Valley during the last ice age that ended about 12,000 years ago. As the glaciers retreated, the Polson terminal moraine, the high rise of land that slopes upwards from the lake to the south was formed. A 27-mile long lake filled in the depression left behind by melting ice, creating Flathead Lake. In more recent history, between 1885 and 1910, steamboats traversed the length of the lake from Demersville on the north to Polson on the south, transporting passengers and freight. The lake is named for the Salish tribe, who were erroneously labeled “flathead” by the Pend d’Oreille tribe, who mistakenly thought the Salish bound their babies on cradleboards, artificially flattening the backs of their heads.

Montana Place Names | Alzada to Zorthman a Montana Historical Society Guide