A black sea of lava, cinder cones, and lava-tube caves — where astronauts trained.
Photo: Supercarwaar · CC BY-SA 4.0 · via Wikimedia Commons
Driving across Idaho's Snake River Plain, the green sagebrush suddenly gives way to a vast, black, broken sea of lava — Craters of the Moon, a volcanic landscape so otherworldly that Apollo astronauts trained here in 1969 to prepare for walking on actual lunar terrain. It's a place of cinder cones, spatter cones, and lava-tube caves, all reachable from a single 7-mile Loop Road, and unlike anything else in the national park system.
The loop strings the highlights together: a short, steep, lung-busting climb up the black cinders of Inferno Cone to a panorama of the Great Rift; the mini-volcano Spatter Cones you can peer into; the Devils Orchard nature walk among lava islands; and the caves. The lava tubes — Indian Tunnel is the biggest and easiest, lit by skylights — require a free cave permit from the visitor center, part of the effort to keep bat-killing white-nose syndrome out (any clothing or gear that's been in another cave is not allowed in).
Two things shape a visit. The heat: the black lava radiates it, with surface temperatures topping 150°F and almost no shade, so summer hikes mean lots of water and early starts. And the season: the Loop Road closes to cars in winter and becomes a ski-and-snowshoe route. Spring through early fall is the window; base in tiny Arco or in Idaho Falls.
The paved scenic drive that links every major feature — cinder cones, spatter cones, the caves, and the nature trails.
Insider tipAllow 2–3 hours to drive it with stops; it closes to cars in winter (becomes a ski/snowshoe route).
Plan a trip to this spot →A short but steep climb straight up a black cinder slope to a 360° panorama of the Great Rift, the Snake River Plain, and distant peaks.
Insider tipThe loose cinders are tiring and there's zero shade — go early or late, bring water, and hold onto your hat (it's windy up top).
Plan a trip to this spot →Indian Tunnel is the biggest and easiest — ~800 feet long with skylights that let in daylight — reached by a metal staircase, with Dewdrop Cave nearby.
Insider tipA free cave permit is required (get it in person at the visitor center) — and any clothing or gear ever used in another cave is banned, to stop white-nose syndrome. Bring a headlamp for the darker tubes.
Plan a trip to this spot →Miniature steep-sided 'mini-volcanoes' built by blobs of lava flung from a vent — short paved walks let you peer down into them.
Insider tipQuick, easy, and very photogenic — a good stop between the bigger hikes.
Plan a trip to this spot →A ½-mile paved, accessible interpretive loop winding through 'lava islands' and gnarled limber pines.
Insider tipA gentle leg-stretcher; the signs explain how life returns to the lava.
Plan a trip to this spot →A ~2-mile round-trip walk to cylindrical molds left where lava encased ancient trees — and the gateway to the backcountry wilderness.
Insider tipMore exposed than the other walks; carry water and sun protection.
Plan a trip to this spot →High desert (~5,900 ft) with big seasonal swings: warm, dry summers (mid-80s°F) and cold, snowy winters. The catch is the black lava — it radiates heat, with rock surfaces over 150°F and almost no shade, so it feels far hotter than the air; carry water and go early in summer. The Loop Road closes to cars in winter for skiing and snowshoeing.
One entrance on the highway between Arco and Carey.
Right on the highway between Arco (~18 mi northeast) and Carey, about 1.5 hours from Idaho Falls. $20/vehicle. Use the visitor center address for GPS to avoid back roads.
One first-come campground in the park; lodging in nearby towns.
The only in-park option — first-come, no hookups, little shade, near the entrance.
Booking tipArrive early in summer; there's no lodge in the park.
The closest town (~18 mi) with small motels and basic services — the natural gateway base.
Booking tipQuirky claim to fame: the first town lit by atomic power.
About 1.5 hours east, with the widest range of hotels and dining.
Booking tipBest if you're combining with a Yellowstone/Teton trip.
What's the entrance fee?
$20 per private vehicle for 7 days ($15 motorcycle, $10 per person; $35 park annual pass; America the Beautiful accepted).
Do I need a permit for the caves?
Yes — a free cave permit, obtained in person at the visitor center. It's part of slowing white-nose syndrome, a disease deadly to bats.
What's the no-gear rule?
Any clothing, footwear, or gear that has ever been in another cave — even if washed — can't be worn or carried into Craters' caves, to prevent spreading the white-nose fungus. Bring items that have never been caving.
How hot does it get?
Summer air tops 90°F, but the black lava radiates heat with surfaces over 150°F and almost no shade. Bring plenty of water and sturdy closed shoes (the lava is jagged), and keep dogs off the hot rock.
Is the Loop Road open in winter?
No — it closes to cars (roughly November–April) and is groomed for cross-country skiing and snowshoeing. Entrance is free during full closures.
What should I bring for the caves?
A headlamp or flashlight for the darker tubes (Indian Tunnel has skylights and is bright; others aren't) — as long as it's gear that's never been in another cave. Footing is uneven, so wear sturdy shoes.
Pick your vehicle, line up the stops on the way in and out, and carry the whole route in your pocket.
