The United States Congress designated the Craters of the Moon National Wilderness Area (map
) in 1970 and it now has a total of 43,243 acres
All of this wilderness is located in Idaho
and is managed by the National Park Service.
Between 15,000 and 2,100 years ago, repeated volcanic eruptions along the Great Rift spilled huge amounts of basalt lava across the Snake River Plain in south central Idaho. After the molten rock cooled, vast lava fields covering over 700 square miles remained, studded with numerous cinder cones and spatter cones, as well as hidden ice caves and lava tubes. While the landscape may appear black and barren, numerous hardy plants (many which bloom colorfully in spring and summer) and animals live in this dry region. While volcanic activity is currently dormant geologists predict the lava will flow in this region again.
A portion of this astonishing landscape, about 83 square miles, was set aside as Craters of the Moon National Monument in 1924. In 2000, an additional 640 square miles of the surrounding Craters of the Moon and adjacent Wapi lava fields were added to the National Park System as Craters of the Moon National Preserve. Most of the Preserve has been recommended for wilderness designation.