What is Crater Lake?

Crater Lake is a large lake located in the Southern Cascade Mountains of Oregon. The lake is distinctive because it formed in the caldera of a volcano which exploded and partially collapsed approximately 7,000 years ago. It is the deepest lake in the United States, and the seventh deepest lake in the world, and holds the distinction of being entirely above sea level, thanks to the high elevation. The lake and surrounding area were designated as a National Park in 1902. 286 square miles (741 kilometers) of area are covered by the National Park, so there is a great deal to explore in addition to Crater Lake itself.

The formation of crater lake began when Mount Mazama erupted, and the upper portion of the volcano collapsed to form a large caldera. The eruption spread volcanic material across much of the Pacific Northwest, and the caldera left behind began to slowly fill thanks to snow and rainfall. Total volume of the ejected material is estimated at at least 150 times more than the material put out by Mount Saint Helens in 1980. There is no inlet or outlet to Crater Lake, and the water level appears to be maintained primarily through snowfall and evaporation, with some seepage.

The depth of the deepest point of Crater Lake has been measured at 1,932 feet (589 meters), and it is six miles (10 kilometers) across at the widest point. Two islands are found in Crater Lake, as well as a population of fish created through the introduction of several fish species in the early 1900s. The lake has a characteristic rich blue color and intensely clear water quality, leading some people to call it the “Jewel of the Cascades.” Crater Lake also has steep sides, because of the way in which it was formed. Visitors to the lake often remark on the highly changeable weather, which can vary from stunning sunny days to overcast, gloomy ones. Layers of clothing are highly advised.

Visitors to Crater Lake can look down from the rim of the caldera, or visit the lake itself. Swimming, fishing, and boating are permitted, although people with disabilities may have trouble reaching the lake, since it is reached by a very steep trail. The surrounding National Park also offers walking and hiking opportunities, and is a popular destination, especially in the summer. Visitors can pay to access the park or use a National Parks Pass. Lodging and other facilities are available seasonally, and reservations are strongly recommended.