Crater Lake National Park, established in 1902 and covering some 183,000 acres, lies in Southern Oregon along the crest of the High Cascades. To the west are the Western Cascades---the older, more eroded line of volcanoes flanking the younger High Cascades---the rugged Klamath Mountains, the Coast Range and the Pacific Ocean. Eastward lie the high desert and basin-and-range country. To the north are other lofty, iconic volcanoes, like the Three Sisters and Mount Jefferson. Southward is Mount McLoughlin and the last Cascade giants in northern California: Shasta and Lassen Peak.
The Mazama Eruption
Mount Mazama, the exploded volcano now cupping Crater Lake, is estimated to have been between 10,000 and 12,000 feet tall before its cataclysmic eruption, the upper scale of which would have made it one of the highest Cascade peaks. (Mount Hood, Oregon's loftiest mountain, is 11,249 feet.) Mazama---produced, like other Cascade vents, by the subduction of the Juan de Fuca tectonic plate under North America---is thought to have erupted about 7,700 years ago. According to the U.S. Geological Survey, ash from the Mazama explosion---42 times larger than that of Mount Saint Helens in 1980---lies across an enormous swath of the western U.S. and three Canadian provinces. The collapse of the volcano's summit resulted in the caldera now occupied by Crater Lake.
Crater Lake's position in Mount Mazama's caldera makes it the deepest in the United States and the ninth in the world; it is nearly 2,000 feet deep at its maximum. Once sealed by lava flows, the caldera filled with water from precipitation and snowmelt. (Crater Lake receives more than 530 inches of snow a year, according to the National Park Service.) The bottom of the caldera features a number of cinder cones, spurred following the main eruption; only one, the famous Wizard Island, rises above the lake's surface. A more ephemeral feature of Crater Lake---but, on human terms, still impressively old---is the Old Man of the Lake, a 30-foot mountain hemlock log that has been floating on the surface since at least 1896.
The blazingly blue lake is the showstopper, but check out the jagged rim of the caldera itself, which reaches over 8,000 feet high in places. Its distinctive promontories---like Cloudcap, the Watchman and Llao Rock---provide breathtaking views. And the Mazama flanks offer their own attractions: The Pumice Desert, sprawling north of the broken summit, is a 5.5-square-mile swath of sparsely vegetated eruption deposits, for example. The famous Pinnacles are scoria and pumice fumarole towers along Wheeler Creek. Mount Scott, a parasitic cone east of the lake, is, at 8,929 feet, the park's highest point.
Elk and mule deer share the montane forests of spruce, fir and lodgepole pine with black bear, martens and bobcats. Remarkably, a pronghorn migration route sometimes takes these fleet ungulates---typically denizens of lower, more open country---from the Fort Rock drylands to the upper drainage of Desert Creek within the national park.
Visiting the Park
Because of Crater Lake's massive snowfalls, the national park's accessible season varies from year to year. Be sure to check the park Web site (see links) or call its headquarters at (541) 594-3000 to plan your visit. A $10 fee admits cars to the park; commercial vehicles pay higher rates. The Rim Drive, which circumnavigates the lake and provides access to some of the park's most well-known vistas and trails, is open only when clear of snow and ice.
There are two campgrounds: Mazama, with 200 sites, is open from the middle of June into the beginning of October and accepts reservations; Lost Creek, with 16 tent-only sites, is open from the middle of July to the beginning of October and is first-come, first-serve. The Crater Lake Lodge and the Mazama Village Motor Inn provide additional lodging opportunities during the summer and early fall.
The park also features two visitor centers, stores and restaurants.