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Glacial Lake Missoula

Glacial Lake Missoula
Glacial Lake Missoula. Photo by S. Corrick.

Glacial Lake Missoula was the largest of several lakes impounded by the Cordilleran Ice Sheet during the Quaternary Period. The site contains the best examples of giant flood ripples in the North American continent. Ripples appear as ridges 15 to 20 feet high, 100 to 250 feet wide, and from 300 feet to one-half mile long.

Location: Sanders County, MT

Year designated: 1966

Acres: 635

Ownership: Private

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Please remember, National Natural Landmarks (NNLs) are not national parks. NNL status does not indicate public ownership, and many sites are not open for visitation.

Last Updated: June 28, 2012