Crater Lake lies inside a caldera, or volcanic basin, created about 7,700 years when the 12,000 foot (3,660 meter) high Mount Mazama collapsed following a major eruption. The lake averages more than 5 miles (8 km) in diameter, and is surrounded by steep rock walls that rise up to 2,000 feet (600 meters) above the lake’s surface. The lake itself is 1,943 feet (592 meters) deep at its deepest point, the deepest lake in the United States and the seventh deepest anywhere in the world. It is fed almost entirely by snowfall, which averages 533 inches (1,354 cm) per year. There is no outlet to the lake; evaporation and seepage prevent the lake from becoming any deeper. The lake level fluctuates slightly from year to year. Its highest recorded level was measured in 1975 when the lake’s surface reached a height of 6,179.34 feet above sea level. The lowest level recorded was 6,163.20 feet (1,878.55 meters), in 1942.

Because Crater Lake is filled almost entirely by snowfall, it is one of the clearest lakes anywhere in the world. Scientists using a reflector called a Secchi disk commonly record clarity readings of 120 feet (37 meters). On June 25, 1997 scientists recorded a record clarity reading of 142 feet (43.3 meters).

Lake temperature varies between 32°F (0°C) and 66°F (19°C) at the surface. More than 260 feet (80 meters) beneath the surface, the water remains 38°F (3°C) year-round. The surface of the lake rarely freezes. The last significant freezing event occurred in 1949, when the entire lake was frozen for more than three months.

A small volcanic island, Wizard Island, rises 764 feet (233 meters) above the surface of the lake on its west side. A small crater, 300 feet (90 meters) across and 90 feet (27 meters) deep, rests on the summit. Crater Lake was named for this beautiful, symmetrical crater by James Sutton, editor of the Oregon Sentinel in Jacksonville, in 1869.

Scientists have identified 157 species of phytoplankton and 12 species of zooplankton in the lake. The density and diversity of these minute life forms is restricted by low concentrations of nitrogen in the lake. Large colonies of moss circle the lake at depths of up to 400 feet (120 meters). At the bottom of the lake, communities of bacteria grow around at least two areas of hydrothermal activity. Two species of fish, rainbow trout and kokanee salmon, also thrive in the lake, the result of stocking between 1888 and 1942.

Greatest depth: 1,943 feet (592 meters) Average depth: 1,148 feet (350 meters) Surface elevation: 6,173 feet (1,881 meters) above sea level Surface area: 13,069 acres (20.42 sq. mi; 5,289 ha.) Widest point: 6.02 miles (9.69 km, Discovery Pt - Grotto Cove) Narrowest point: 4.54 miles (7.31 km, Dutton Cliff - Llao Rock) Average height of rim: 1,000 feet (300 meters) above the water Highest point on rim: 1,980 feet (604 meters) at Hillman Peak Lowest point on rim: 507 feet (155 meters) at Palisade Point Wizard Island: 764 feet (233 meters) above the water Volume of water: 5 trillion gallons (19 trillion liters)

Total Area: 183,224.05 acres (286 sq. mi.; 78,117 ha)

• Crater Lake: 13,760 acres (7.5%)
• Munson Valley Historic District: 7.5 acres

Maintained trails: 90 miles (145 km)

• Pacific Crest Trail: 33 miles (53 km)

Roads: 79 miles (127 km)

• Paved: 74 miles (119 km)
• Rim Drive: 33 miles (53 km)

Elevations:

• Highest point in park: 8,929 feet (2,721 meters) at Mount Scott
• Rim Village: 7,100 feet (2,165 meters)
• Park Headquarters: 6,450 feet (1,966 meters)
• Mazama Village: 6,004 feet (1,803 meters)
• Lowest point in park: 3,977 feet (1,212 meters) at Red Blanket Canyon

Plants and Animals

Plant species: 700

• Rare, endangered, or of special concern: 17
• Non-native species: 49

Animal species:

• Mammals: 52
• Birds: 151
• Amphibians: 8
• Reptiles: 4
• Fish: 5 (1 native, 4 planted)
• Threatened: 3 (wolverine, northern spotted owl, American bald eagle)

Precipitation:

• Average precipitation: 69 inches (175 cm)
• Average snowfall: 533 inches (1,354 cm)
• Minimum annual snowfall: 243 inches (617 cm, 1991-92)
• Maximum annual snowfall: 879 inches (2,233 cm, 1932-33)
• Maximum recorded snowpack: 252 inches (640 cm, 1983)

Temperatures from January to March average 19°F (-7°C) at night and 36°F (2°C) during the day. Temperatures from July to September average 40°F (4°C) at night and 70°F (21°C) during the day.

Crater Lake averages about 500,000 visitors per year.

1998 statistics:

• Total visitors: 521,465
• Wilderness backpackers: 1,214

Single, private, non-commercial vehicles: $10
Pedestrians, single motorcyclists, and bicyclists: $5
Commercial buses: $25 to $200, depending on capacity

During the summer, guided walks, talks, campfire programs, and junior ranger programs are offered by the National Park Service. Interpretive boat tours are offered in cooperation with the Crater Lake Lodge Company. During the winter, the National Park Service offers guided snowshoe walks.

A concession company provides lodging, gifts, gas, camping, and food service in the park during the summer. Food service and gifts are available during the winter. For information, call (541) 830-8700.

Full services are also available in local communities year-round.

Natural History Association
The Crater Lake Natural History Association is a non-profit organization dedicated to advancing educational and scientific activities within Crater Lake National Park and Oregon Caves National Monument. Books, maps, and postcards are available for sale at all park visitor centers. For information, write to P.O. Box 157, Crater Lake, OR 97604, or call (541) 594-3110.

Friends of Crater Lake
The Friends of Crater Lake is a non-profit organization that cooperates with the National Park Service in the stewardship of Crater Lake National Park’s natural and cultural resources. For information, write to P.O. Box 88, Crater Lake, OR 97604; send e-mail to greddell@cvc.net; or visit www.drizzle.com/~rdpayne/foclnp.html on the World Wide Web.

P.O. Box 7, Crater Lake, OR 97604
(541) 594-3000
www.nps.gov/crla

Superintendent of Crater Lake National Park: Charles V. Lundy

Secretary of the Interior: Gale Norton
Director of the National Park Service: Fran P. Mainella
Pacific West Regional Director: John Reynolds

Rev. 11/2001 klb