Established in 1924, Craters of the Moon National Monument celebrated its 75th birthday in 1999. In November 2000, a Presidential proclamation greatly expanded the Monument area. The National Park Service portions of the expanded Monument were designated as a National Preserve in August 2002. The area is managed cooperatively by the National Park Service and the Bureau of Land Management(BLM).
The Monument and Preserve encompass three major lava fields and 250,000 acres of sagebrush steppe grasslands. The rugged landscape remains remote and undeveloped with only one paved road across the northern end. Traditional livestock grazing continues within the grass/shrublands administered by BLM.
The Craters of the Moon lava field spreads across 618 square miles and is the largest young basaltic lava field in the lower 48 states. The Monument and Preserve contain more than 25 volcanic cones including outstanding examples of spatter cones. Sixty distinct lava flows form the Craters of the Moon lava field ranging in age from 15,000 to just 2,000 years old.
The Kings Bowl and Wapi lava fields, both about 2,200 years old, are now part of the National Preserve. All three lava fields lie along the Great Rift, with some of the best examples of open rift cracks in the world. There are excellent examples of pahoehoe, slabby pahoehoe, shelly pahoehoe, spiny pahoehoe, aa, and block lava, as well as rafted blocks, tree molds, lava tubes, and many other volcanic features.