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. Two lava tubes are still open — Indian Tunnel, the biggest and easiest, lit by its own collapsed skylights, and the smaller, darker Dewdrop Cave. Boy Scout, Beauty and Buffalo caves are closed for good to protect the bats. Both open caves need a free permit, picked up in person at 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 rock surfaces reaching 170°F and almost no shade, so summer hikes mean lots of water and early starts. And the season: the Loop Road closes to cars from about mid-November to mid-April and becomes a ski-and-snowshoe route. Spring through early fall is the window; base in tiny Arco or in Idaho Falls.
Craters of the Moon is a seven-mile loop through a lava field on the Idaho plain, and for about five months of the year you cannot drive it. The road closes to vehicles from roughly mid-November to mid-April — but it stays open to skis and snowshoes, which is a genuinely different way to see a lava flow and one almost nobody takes.
The highway between Arco and Carey runs along the monument’s northern edge, with the entrance directly off it. It is the main route across southern Idaho, so this is a stop rather than a destination for most people.
Seven miles of paved one-way loop off the entrance road, with the cinder cones, spatter cones and cave trailheads all signed from it. Everything the monument is known for is a short walk from this road. It is paved the whole way and fine for RVs, with parking at the visitor center and the main pullouts.
The interstates are a long way off: roughly 85 miles east to I-15 at Idaho Falls, about 90 miles south to I-84 at Twin Falls. Those two are the nearest cities of size, and the drive in across the Snake River Plain is flat, empty and a good build-up to what arrives.
Closed to motor vehicles roughly mid-November to mid-April, but open to skiers and snowshoers
Short enough to drive in twenty minutes and worth two hours, because everything is a five-minute walk off it — Inferno Cone, the spatter cones, the cave trailheads. In winter the same seven miles become a ski and snowshoe route across black rock and white snow.
TipPick up the free cave permit at the visitor center before you start the loop, and bring a light — it is only issued in person. In summer the black lava gets extremely hot and there is no shade anywhere on the loop.
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 is paved and fine for RVs, and it closes to cars from about mid-November to mid-April, when it becomes a ski and 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 — about 800 feet long, with collapsed skylights that let in daylight — reached by a metal staircase. Dewdrop Cave, on the same trail, is the only other cave still open.
Insider tipThe free cave permit has to be picked up in person at the visitor center during business hours — an annual pass does not count as one, and the never-been-in-another-cave gear rule applies. Bring a light for Dewdrop; Indian Tunnel's skylights do the work.
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 that can drop below 0°F. The catch is the black lava — it radiates heat, with rock surfaces reaching 170°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 from about mid-November to mid-April.
One entrance on the highway between Arco and Carey.
Right on the highway, 18 mi southwest of Arco and 24 mi northeast of Carey, about 1.5 hours from Idaho Falls. $20/vehicle. The Loop Road is paved and fine for RVs. Use the visitor center address for GPS — 1266 Craters Loop Road — because navigation apps here like to send people down unpaved back roads.
One first-come campground in the park; lodging in nearby towns.
The only in-park option — first-come, first-served, no hookups, little shade, right by the visitor center.
Booking tipClaim a site, then register at the automated fee machine, which takes credit cards only. No wood fires; charcoal grills are fine. Water and flush toilets are seasonal, and there is 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 16 and older; under 16 free). A park annual pass is $35 and the $80 America the Beautiful pass works.
Do I need a permit for the caves?
Yes — a free permit, issued only in person at the visitor center during business hours. An America the Beautiful or park annual pass does not count as a cave permit. 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 highs sit in the mid-80s and push past 90°F on the hottest days, but the black lava radiates heat with rock surfaces reaching 170°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 from about mid-November to mid-April and is open to cross-country skiing and snowshoeing. Entrance is free the whole time it's closed.
What should I bring for the caves?
A headlamp or flashlight for Dewdrop Cave — Indian Tunnel's skylights keep it bright, Dewdrop has none. Those two are the only caves open; Boy Scout, Beauty and Buffalo are permanently closed to protect bats. 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.
