Craters of the Moon National Monument
1266 Craters Loop Rd
Arco, ID
A sea of black lava, cinder cones, and lava-tube caves so strange that NASA sent Apollo astronauts here to learn how to explore another world.
Craters of the Moon National Monument protects one of the most surreal landscapes in the United States: a rippling, black expanse of hardened lava, cinder cones, and deep cracks spread across the high plain of central Idaho. The name is no exaggeration. The ground looks so much like another planet that in 1969 NASA brought Apollo astronauts here to study volcanic geology before they walked on the Moon.
Yet this is not the leftover of some single ancient cataclysm. The lava here is young by geologic standards, and the forces that made it are only sleeping. Craters of the Moon is one of the youngest volcanic areas in Idaho, and geologists consider it among the most likely places in the state to erupt again.
What Guests Love
- Driving and walking through a genuinely lunar landscape of black lava, spatter cones, and cinder gardens
- Climbing Inferno Cone for a sweeping view over the whole volcanic field
- Exploring lava-tube caves with a headlamp on the Caves Trail
- Some of the darkest skies in the country, certified for stargazing
Worth Knowing
- Caving requires a free permit and clean gear to protect bats from white-nose syndrome; ask at the visitor center
- The black lava radiates heat, so summer days are brutally hot with almost no shade; carry lots of water
- The scenic Loop Road typically closes with snow in winter, when the field becomes a ski and snowshoe route
- An entrance fee applies, and footing on lava is sharp and uneven, so wear sturdy shoes
Details
Arco, ID
Learn about Craters of the Moon National Monument
The Great Rift and eight ages of fire
The heart of the monument is the Great Rift, a system of cracks in the earth's crust running about 62 miles across the Snake River Plain. Instead of a single volcano, lava here welled up from these long fissures, spreading in sheets and building cinder cones, spatter cones, and lava tubes.
The eruptions came in roughly eight major pulses between about 15,000 and 2,000 years ago, with the most recent ending around 2,100 years ago. Because they are so young and this desert is so dry, the flows are remarkably fresh, and scientists note that with eruptions about every 3,000 years, the field is likely only dormant, not dead.
Walking the volcanic field
A loop road and a set of short trails put the landscape within easy reach. You can climb the steep black slope of Inferno Cone for a panorama over the whole field, wander the delicate Spatter Cones, and cross flows named for their ropey and rubbly textures.
The Caves Trail leads to lava tubes, tunnels left where the surface of a flow hardened while molten rock drained away beneath. With a headlamp and a free permit, you can step underground into the cool dark of caves like Indian Tunnel and Boy Scout Cave.
A Shoshone and Bannock homeland
People have known this place for a very long time. Archaeological evidence shows Shoshone people visited the area as far back as roughly 12,000 years ago, and it is likely they witnessed some of the eruptions. Northern Shoshone shelters, hunting blinds, and tool sites remain, including places where they gathered a glassy lava for making arrow points.
Craters of the Moon lies within the ancestral homelands of the Shoshone and Bannock peoples, who traveled through it for thousands of years between salmon-fishing rivers, buffalo grounds, and camas-digging meadows. Their descendants remain in the region, and the monument now works to tell that history in their own words.
Wildlife, dark skies, and seasons
Life is tougher to spot here but it is present: pikas and marmots in the rubble, mule deer and pronghorn on the sage flats, and wildflowers like dwarf buckwheat and monkeyflower that bloom brilliantly against the black cinders in early summer.
The monument is certified for its dark skies, and on a clear night the stars over the lava are extraordinary. Late spring and early summer bring wildflowers and tolerable temperatures; midsummer is punishingly hot on the black rock; and winter closes the Loop Road to cars but opens it to skiers and snowshoers.
Closest Boutels
The closest Boutel™ stays, so you can turn this stop into an overnight. Each is an independently owned, editorially selected place to stay.
Things to Do Near Arco
Arco
About 18 miles northeast
A small high-desert town billed as the first community powered by nuclear energy, with the Number Hill carved by graduating classes.
EBR-1 Atomic Museum
About 30 miles east
The world's first electricity-generating nuclear reactor, now a free museum on the desert east of Arco.
Fort Hall Bottoms and the Snake River Plain
About 70 miles southeast
The Shoshone-Bannock homeland along the Snake near Pocatello, with wetlands, wildlife, and rich living culture.