Mount Mazama . Mount Mazama is a complex volcano in the American part of the Cascade Range whose collapsed caldera holds Crater Lake (pictured), the nation's deepest freshwater body, at 1,943 feet (592 m). In North America, only Great Slave Lake in Canada is deeper. Mount Mazama, within Crater Lake National Park, is in the Oregon segment of the Cascade Volcanic Arc. The mountain's elevation before its climactic eruption about 7,700 years ago was around 12,000 feet (3,700 m), but is now 8,157 feet (2,486 m). Mount Mazama formed as a group of overlapping volcanic edifices including shield volcanoes and small composite cones, becoming active intermittently until its big eruption. Mazama is dormant, but the United States Geological Survey says that eruptions on a smaller scale are likely, and that these could pose a threat to its surroundings. Indigenous people have inhabited the area around Mazama and Crater Lake for at least 10,000 years.