Flathead Lake

General data
- Name: Flathead Lake
- Water system: Columbia River
- Water type: Artificial lake
- Progression: Flathead River -> Clark Fork River -> Lake Pend Oreille -> Pend Oreille River -> Columbia River -> Columbia River Estuary -> Pacific Ocean -> Planet Earth
- Climates: Temperate
- Continents: North America
- Countries: United States of America
Description
Flathead Lake is a large natural lake in northwest Montana, United States. The lake is a remnant of the ancient, massive glacial dammed lake, Lake Missoula, of the era of the last interglacial. Flathead Lake is a natural lake along the mainline of the Flathead River. It was dammed in 1930 by Kerr Dam at its outlet on Polson Bay, slightly raising the lake level; the dam generates electricity. The hydroelectric has been owned and operated by the Confederated Salish and Kootenai Tribes since 2015. It is one of the cleanest lakes in the populated world for its size and type.