With an average depth of 1,932 feet, Crater Lake is the deepest lake in the United States, and the 7th deepest in the world.

Crater Lake partially fills the caldera of ancient Mount Mazama Volcano, the summit of which collapsed thousands of years ago. At the time of its collapse, the mountain was about 14,000 feet high, but it now only rises about 6,000 feet above sea level. The lake was created over about 250 years by an accumulation of rain and melted snow, and precipitation continues to keep the lake full today. Since the average annual precipitation on the summit equals the evaporation and seepage rate, the level of the lake has only varied over a range of 16 feet in the past 16 years. And, since there are no other inlets into the lake, the waters of Crater Lake are incredibly clear; on an average day it is possible to see down as much as 90-100 feet.

The Klamath Indians believed the lake's waters had healing qualities. The first white man to see the lake appears to have been mining prospector John Hillman, in 1853. Crater Lake National Park, which includes the area around the ancient volcano, was created in 1902. The park's official website is www.nps.gov/crla.

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This page was last updated on May 04, 2017.