Craters of the Moon National Monument and Preserve

Craters of the Moon National Monument and Preserve protects three major lava fields and about 400 square miles of sagebrush steppe grassland along the Snake River Plain in central Idaho, for a combined area of 1,117 square miles. It lies along US Highway 20, between the towns of Arco and Carey, at an average elevation of about 5,900 feet, and spans Blaine, Butte, Lincoln, Minidoka and Power counties. The monument was established on May 2, 1924; a presidential proclamation in November 2000 greatly expanded its area, and in August 2002 the expanded National Park Service portions were redesignated as Craters of the Moon National Preserve, while the site continues to be managed jointly by the National Park Service and the Bureau of Land Management. All three lava fields lie along the Great Rift of Idaho, whose open rift cracks include what is described as the deepest known on Earth, at 800 feet. The site preserves varied basaltic lava features including tree molds and lava tubes.