NASA trained astronauts here, and you can walk the same lava fields in Idaho

It’s not the moon, but astronauts trained here

Central Idaho has a stretch of land that looks like nothing else in the country. Lava fields roll out for miles.

Cinder cones rise from the flat plain. Caves tunnel beneath your feet.

Craters of the Moon National Monument and Preserve covers 1,117 square miles of this volcanic terrain, and a single seven-mile road takes you through nearly all of it.

The reason NASA sent astronauts here before the moon landing is only the beginning of the story.

A 53-mile crack runs beneath this Idaho plain

The ground here is still telling you something happened.

The whole monument sits along the Great Rift, a roughly 53-mile crack in the earth’s crust that holds the deepest known open volcanic rift on the planet at 800 feet down.

Eight major eruptions shaped this landscape over the past 15,000 years, with the most recent about 2,000 years ago.

The lava field stretching across the Snake River Plain covers about 618 square miles, making it the largest mostly Holocene-aged basaltic lava field in the contiguous United States.

One magazine article put this place on the map

Explorer Robert Limbert hiked and mapped the lava fields in the early 1920s, then published a photo essay in National Geographic in 1924.

Within two months, President Calvin Coolidge signed the monument into existence, calling it a “weird and scenic landscape.”

The monument sat at about 54,000 acres for decades until President Clinton expanded it in 2000 to cover the entire Great Rift zone.

Today the National Park Service and the Bureau of Land Management share responsibility for it. In 1969, four Apollo astronauts came here to study geology before their moon missions.

Seven miles of road, every type of volcano you can name

The main loop road runs seven miles and hits almost everything.

Pullouts and short trailheads branch off in both directions, giving you access to lava flows, cinder cones, and spatter cones without a long commitment.

Even if you stay in the car, the Pioneer Mountains rise in the distance beyond miles of black rock and the contrast stays with you. The road runs from late April or May through late November, depending on snow.

Plan around that window, because when it closes, the whole dynamic of the place changes.

Duck into a lava tube 800 feet long

The Caves Trail leads you to four lava tubes you can actually walk into. Indian Tunnel is the one to start with.

It runs about 800 feet long and 30 feet tall, and sections of the ceiling have collapsed over time, letting daylight fall in at angles through the gaps.

Boy Scout Cave, Beauty Cave, and Dewdrop Cave go darker fast and require a flashlight or headlamp. Before you enter any of them, you need a free cave permit from the visitor center.

The process protects bat colonies inside from a disease that spreads on clothing worn in other caves.

Climb a cinder cone for views into three mountain ranges

Inferno Cone looks steep from the parking area, and it is.

The trail climbs 164 feet in about 0.4 miles round trip, and every step sinks a little into loose volcanic cinders.

At the top, the Snake River Plain spreads out in every direction, the Great Rift cuts across the landscape below you, and on a clear day, the Teton Range sits on the horizon about 100 miles to the east.

The cone has no shade and the dark surface holds heat, so summer mornings are better than afternoons up there.

Peer straight down into the throat of a spatter cone

Most people drive past the Spatter Cones area without realizing what they’re looking at. These small formations built up when blobs of molten lava landed around a vent and cooled into cone-shaped walls.

You can walk right up to the rim and look directly down into the vent opening.

One of them, the Snow Cone, has a deep narrow crater where snow collects and often holds on into summer.

There are few places in the country where you can stand at the edge of a volcanic formation and look straight into it like this.

Short trails cross the lava fields in every direction

The 1.8-mile Broken Top Loop circles a volcano and passes lava bombs scattered across the rock. The North Crater Trail runs another 1.8 miles through a crater and connects toward the Spatter Cones area.

If you want something flat and accessible, the Devil’s Orchard Nature Trail is a paved 0.5-mile path with geology exhibits that works for strollers and wheelchairs.

The Tree Molds Trail takes you to cavities where lava surrounded standing trees thousands of years ago, burned them away, and left behind their exact shapes in the rock.

Wildflowers push through cracks in the lava every spring

The landscape looks like nothing should grow here, but more than 700 plant species do.

Each spring, dwarf monkeyflower, bitterroot, dwarf buckwheat, and Indian paintbrush work through splits in the lava rock, spreading color across fields of black cinders.

Some plants survive by sending roots down through those cracks where surface temperatures can hit 150 degrees. Peak blooms run from late May through June, though flowers can appear from early May into September.

The contrast between the dark rock and the color coming through it is something the photos don’t quite capture.

Pronghorn cross here and bats sleep underground

More than 200 bird species live in or pass through the monument, which surprises most people on their first visit. Birds and rodents are the animals you’ll spot most often.

Pronghorn migrate across the northern Snake River Plain, and the park modified its boundary fencing so wildlife can move through without getting stopped.

The lava tube caves shelter bat colonies and cave-dwelling invertebrates.

Above ground, limber pines grow twisted at strange angles from decades of constant wind across the exposed plain.

The Milky Way runs clear across the sky on moonless nights

Craters of the Moon earned its International Dark Sky Park designation in 2017, and on a moonless night, the Milky Way cuts straight across the sky from horizon to horizon.

The monument sits at the edge of one of the largest remaining dark sky areas in the lower 48 states, and the sparse population for miles around means almost no light pollution reaches the plain.

The Idaho Falls Astronomical Society has run star party events here for more than 25 years. Ranger-led stargazing programs run in summer if you want someone to walk you through what you’re seeing.

Winter flips the whole place into a cross-country ski trail

When the loop road closes to cars, it converts to a groomed seven-mile ski and snowshoe trail that typically runs from December through March.

The black cinder cones disappear under snow and the whole landscape turns into a stark black-and-white pattern that looks nothing like the summer version.

Rangers lead guided snowshoe hikes on Saturdays in January and February.

Come prepared for cold and wind, because the plain offers nothing in the way of shelter and the exposed terrain catches every gust that crosses it.

Know these things before you leave home

The Robert Limbert Visitor Center near the park entrance runs a short film on the geology and keeps staff on hand for ranger program schedules.

Pick up your free cave permit there before heading to the Caves Trail.

There’s no food or lodging inside the monument, and the nearest services sit in Arco, about 18 miles east. The monument runs along US Highway 20/26/93 between Arco and Carey.

Bring water, sun protection, and closed-toe shoes. The lava rock cuts through light footwear faster than you’d expect.

Visit Craters of the Moon National Monument and Preserve in Idaho

You can reach Craters of the Moon by taking US Highway 20/26/93 between the towns of Arco and Carey in central Idaho, about 84 miles from Idaho Falls and 90 miles from Twin Falls.

The monument sits roughly midway between Boise and Yellowstone. The Lava Flow Campground inside the monument has 42 first-come, first-served sites with no hookups.

Admission is $25 per vehicle and covers a seven-day pass.

Check the National Park Service’s official website for current road conditions, cave permit hours, and seasonal program schedules before you go.

This article was created with AI assistance and human editing.

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