ARCO, Idaho — Craters of the Moon National Monument is a weird place. President Calvin Coolidge even said so in his May 2, 1924, proclamation, which described the otherworldly landscape: “this area contains many curious and unusual phenomena of great educational value and has a weird and scenic landscape peculiar to itself.”
One hundred years since its establishment, the monument remains a geological highlight reel of volcanic forms that could rival Hawaii or Iceland without having to leave the Pacific Northwest. (And don’t let that “national monument” designation deter you. Craters of the Moon offers national park-quality visitor experience without the crowds.)
For the monument’s 100th birthday this year, the National Park Service is celebrating with spruced-up visitor infrastructure, a full slate of guided hikes and stargazing parties, as well as a renewed relationship with the Shoshone-Bannock Tribes, the region’s original inhabitants.
Read on for details about visiting this unique lunar landscape in its centennial year.
Getting there and where to stay
Coolidge never set foot in Idaho, but he was enamored with explorer Robert “Two-Gun Bob” Limbert’s March 1924 National Geographic story that recounted his arduous expeditions through the state’s lava fields. Limbert went on to lobby the president to protect the remarkable area. A hardy crowd of 1,500 braved gravel and cinder roads to reach the dedication ceremony on June 15, 1924.
One hundred years later to the month, I had a much easier time getting to this remote patch of the Gem State on roads freshly paved for the centennial. The monument is 670 miles (about 10 hours) by car from Seattle. The nearest airports to Craters are Boise (2 3/4 hours drive) and Idaho Falls (1 1/2 hours drive). The latter is closer, but has fewer nonstop flights from Seattle (twice daily on Alaska Airlines) compared to Idaho’s capital (17 times daily on Alaska Airlines and Delta). If you are road-tripping through southern Idaho, Pocatello and Twin Falls are larger interstate-adjacent cities within easy reach of Craters.
Craters of the Moon National Monument
100 years ago, President Calvin Coolidge signed a proclamation declaring Craters of the Moon National Monument in southern Idaho as a “weird and scenic landscape peculiar to itself.”
The 42-site Lava Flow Campground offers the only accommodations inside the monument ($15 per night, no RV hookups available). The sites are first come, first served, so arrive early if you want to sleep in the park. Nearby Arco, 19 miles away, has private campgrounds and motels, as well as basic services like gas, groceries, restaurants and a medical clinic (more on that amenity later).
Plan to bring sufficient food for your stay, whether a day trip or overnight, and carry ample water in the heat of the high desert. (The visitor center and campground typically close by Thanksgiving when the first snows arrive, though bathrooms remain open for intrepid winter explorers.)
Moonwalking
Whether you are a volcanology geek who knows your smooth pahoehoe lava from your rough a’a lava (two Native Hawaiian terms that have become universal nomenclature) or you simply enjoy marveling at visually arresting natural wonders, Craters of the Moon offers an impressive range of geologic formations.
Unlike the gargantuan Cascades volcanoes covered in snow and ice most or all of the year, the spatter and cinder cones sprinkled throughout Craters are comparatively small volcanoes easy to admire up close in the summer and fall.
While the larger preserve encompasses a vast 1,172 square miles, the monument serves up a volcanic sampler platter on a compact slice of terrain immediately past the visitor center. Ambitious visitors can probably tick off every last trail and viewpoint in a day, but this easy-access portion of the monument is best suited to two days.
Driving from the park entrance to the farthest trailhead barely takes 15 minutes. Along the way, seven stops tempt you with short hikes (from 0.3 to 2 miles) illustrating the aftermath of eruptions that occurred from 15,000 to 2,100 years ago. You’ll spy cinder cones (the classic steep, conical shape topped with a crater) as well as monoliths (towering chunks of igneous rock carried to their present spot by lava flows). Beneath the surface, lava tubes — underground passageways created by flowing lava — beckon for cavelike exploration.
Start with the North Crater Flow Trail, where a 0.3-mile boardwalk winds past multiple types of lava, including the evocatively named blue dragon variety; a type of monolith known as a rafted block; and a 1,350-year-old tree that grew in the wake of a molten lava flow.
For a tougher but equally informative hike, tackle the 1.8-mile Broken Top Loop Trail that likewise encounters most of the main volcanic features in the park, with bonus views from the Big Sink Overlook onto the remnants of an old lava pond.
On both hikes, I watched for subtle clues based on what Sarah Rogers, executive director of the Craters of the Moon Natural History Association, told me: “You can tell which volcanoes are oldest because of how much vegetation is on them.”
Southern Idaho’s recent eruptions haven’t weathered into fertile volcanic loam — what little plant life grows relies on soil blown in from elsewhere. You can also read the landscape to understand the interaction between wind and vegetation. (“On the backsides, you’ll see which way the wind blows based on how the limber pines are twisting and turning,” Rogers said.)
While the 700-plus plant species that cling to life in the harsh landscape are admirable, I was most taken with the flora-free Inferno Cone, which, simply put, felt the most lunar. Here was the kind of otherworldly setting that I could imagine inspired NASA brass to send four Apollo 14 astronauts to Craters on a 1969 training mission.
The short but steepish 0.4-mile jaunt to the top offers the best unobstructed panorama in Craters, where you can appreciate the vastness of the landscape — especially the Great Rift backcountry wilderness to the south, which I only saw the edge of when hiking out from Broken Top. To commemorate the centennial, a group of four Idahoans backpacked the 65-mile rift. Few have completed that arduous trek across a landscape of scarce water, tricky footing and few flat patches of ground for sleeping.
For an easier path, plan a visit around ranger-led full moon hikes (Aug. 18-19, Sept. 15), geology hikes (Aug. 24) and wildlife photography clinics (Sept. 28).
Below and above ground
To fully appreciate Craters of the Moon, you’ll have to go below ground — and look high above. Multiple lava tubes with entrances exposed to the surface populate the monument. Two of them, Dewdrop Cave and Indian Tunnel, are open to the public and accessible via a 0.8-mile paved trail through the lava.
First, make sure to acquire your free cave permit at the visitor center. To avoid spreading the bat-killing white-nose syndrome, you cannot bring any clothing or equipment that has previously been in another cave, even if you’ve washed the item. So if you’ve ever mucked around any of the caves in the Cascades, make sure to bring a different outfit and boots.
A flashlight or headlamp are highly recommended, but even carrying one of those didn’t prevent me from making a rookie mistake.
After appreciating the damp coolness of Indian Tunnel — and marveling at the sight of moisture in this parched land — I approached the narrow exit, jerked my head up too soon and bashed my skull on the sharp lava rock. I ended up with a laceration that required staples, which staff at the aforementioned Arco medical clinic ably took care of. As the first lava rock victim of the season, my arrival, they said, was a sure sign of summer.
Fortunately, I was stitched up quickly enough to return in time for the monthly star party (next on Sept. 6-7), which draws in volunteers from local astronomy clubs who set up an array of telescopes at trailheads. After sunset, several dozen visitors — ranging from Idaho National Laboratory summer interns and RV-dwelling retirees to young couples and parent-child pairs on national park road trips — bundled up against the desert chill and took turns peering into the cosmos.
Eric Laing, former president of the Idaho Falls Astronomy Society, eagerly made the trip out to Craters, one of Idaho’s four locales certified by DarkSky International. (Oregon has one; Washington has none.) The monument scores 2 on the Bortle scale, a universal measurement of dark skies, which is almost as good as it gets on the planet. “It’s one of the few places that is remote enough from any city lights for truly dark sky,” he said.
I spied the Hercules globular cluster of some 500,000 stars through Laing’s cannon-looking telescope before I returned to the campground and crawled into my tent. The next morning, he told me that the die-hards stayed up until 2:30 a.m. observing galaxies and nebulae around the Big Dipper.
Science and creation stories
The ranger talk that preceded the June star party riffed on how staring at the night sky has prompted myths and stories, like the constellations named after recognizable objects — a belt, a spoon, a crown — even as early astronomers sought a more rigorous scientific explanation.
That dynamic also plays out at Craters. While we rightly celebrate the scientific accomplishment of 20th-century geologists who can deduce the timeline of volcanic eruptions that took place thousands of years ago, there is also something equally compelling about the Shoshone-Bannock creation story. According to their tradition, a great serpent that once occupied the Snake River squeezed the mountains until they produced fire and lava, which in turn cooked the serpent to death — its charred remains now etched into the rock.
The Shoshone and Bannock regularly traveled through the lava fields en route to hunting and gathering grounds. In September, the Park Service will install new interpretive signage at the Devils Orchard trailhead prepared in collaboration with the tribes, which lauded the federal government for “fostering mutual respect” in its management of a place members know as Tennambo’i, or “Antelope’s Trail.” (For a deeper understanding, visit the Shoshone Bannock Tribal Museum outside Pocatello.)
The archaeological record suggests that tribal members were present during some of the eruptions along the Great Rift, the monument’s volcanic backbone where tectonic plates pulled apart. It’s the kind of dramatic natural phenomenon that would have inspired the creation story. Today scientists believe that Craters will be the location of Idaho’s next volcanic eruption, very possibly during our lifetimes, an event that will surely inspire equal parts rigorous research and cosmic awe.
