Mount Mazama lies in Klamath County, within the U.S. state of Oregon, 60 miles (97 km) north of the border between Oregon and California state, in the southern portion of the Cascade Range. Inside the volcano's caldera lies Crater Lake, which has a depth of 1,943 feet (592 m) and thus represents the deepest body of freshwater in the United States. Before its caldera-forming eruption, Mazama stood at an elevation between 10,800 to 12,100 feet (3,300 to 3,700 m), placing it about 1 mile (1.6 km) above the lake and making it Oregon's highest peak. The Global Volcanism Program currently lists its elevation at 8,159 feet (2,487 m), while the Geographic Names Information System provides an elevation of 6,174 feet (1,882 m).
Crater Lake National Park
Crater Lake National Park covers an area of 250 square miles (650 km2), including forest areas, alpine terrain, the Crater Lake, and the vast majority of Mount Mazama. A wilderness area, it was dedicated in 1902 and is overseen by the National Park Service. It receives about 500,000 visitors each year, and these tourists can go hiking, take bike, ranger-guided, and trolley tours, swim, fish, camp, and participate in other recreational activities. While the Park area remains open throughout the year, certain roads and facilities close in the winter season.
Glaciers formed on the mountain over and over as Mazama developed. They carved trenches in the flanks of the volcano in addition to U-shaped valleys under the base of the volcanic cone. These can be observed at three large glacial canyons on its southern slopes: Kerr Notch, Munson Balley, and Sun Notch. Whenever eruptions took place in the presence of ice, lava was chilled by glaciers, creating glassy talus deposits. Sometimes, the lava coursed into areas previously carved by glaciers like at Sentinel Rock, filling canyons with volcanic rock. Moraines occur up to 17 miles (27 km) from the rim of Mazama's caldera and there are glacial striations visible at several sites in the area. The most recent period of glacial advance ceased about 27,000 years ago, so by the time Mazama collapsed in its climactic eruption, ice was likely only present at higher elevations.