Crater Lake is located in Southern Oregon on the crest of the Cascade Mountain range, 100 miles east of the Pacific Ocean. It lies inside a caldera, or volcanic basin, created when the 12,000 foot high Mount Mazama collapsed 7,700 years ago following a large eruption.
Generous amounts of winter snow, averaging 533 inches per year, supply the lake with water. There are no inlets or outlets to the lake. Crater Lake, at 1,943 feet deep, is the seventh deepest lake in the world and the deepest in the United States.