Glacial Lake Missoula

Prehistoric proglacial lake in Western Montana

Lake Missoula was a prehistoric proglacial lake in western Montana that existed periodically at the end of the last ice age between 15,000 and 13,000 years ago. The lake measured about 3,000 square miles (7,770 km²) and contained about 500 cubic miles (2,100 km³) of water, half the volume of Lake Michigan. The Glacial Lake Missoula National Natural Landmark is located about 68 miles (110 km) northwest of Missoula, Montana, at the north end of the Camas Prairie Valley, just east of Montana Highway 382 and Macfarlane Ranch.

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