Craters of the Moon National Monument

State: Idaho. Type: national monument and preserve protecting a vast volcanic lava field in south-central Idaho, along the Great Rift. Contains the largest young lava field in the lower 48 states, with flows roughly 2,000 to 15,000 years old. Designated an International Dark Sky Park in 2017. Entrance fee: $20 per private vehicle (valid 7 days). Address: 1266 Craters Loop Road, P.O. Box 29, Arco, ID 83213. Phone: 208-527-1300.

Craters of the Moon National Monument and Preserve protects a sweeping volcanic landscape in south-central Idaho that the National Park Service calls a "weird and scenic" expanse of lava and sagebrush. It encompasses the largest young lava field in the lower 48 states, spread across the Great Rift volcanic zone, a series of deep fissures in the earth's crust. The lava flows here are geologically recent, ranging from roughly 2,000 to 15,000 years old, and the terrain is studded with cinder cones, spatter cones and lava tubes that visitors can hike and explore. A scenic Loop Road threads through the northern part of the monument, connecting trailheads, cinder cones and cave areas, while a vast wilderness and preserve stretch beyond for backcountry travelers. The landscape is so otherworldly that it has drawn comparisons to the surface of the moon, and NASA astronauts once trained here. In 2017 the monument was designated an International Dark Sky Park, recognizing its exceptionally dark night skies for stargazing. Managed jointly with the Bureau of Land Management, Craters of the Moon offers hiking, caving, camping and astronomy in a stark, memorable setting unlike anywhere else in Idaho.

Craters of the Moon is in south-central Idaho, with its entrance directly off U.S. Highway 20/26/93. The monument's address is 1266 Craters Loop Road, Arco, ID 83213, and the small town of Arco lies about 18 miles to the northeast, with Carey to the west. The site protects the largest young lava field in the lower 48 states across the Great Rift volcanic zone. A 7-mile Loop Road provides the main developed access through the northern portion.

Craters of the Moon sits in Idaho's high desert, and its dark, exposed lava surfaces can make conditions feel extreme. Summers are hot and dry, with the black basalt absorbing heat and little natural shade on the lava fields. Winters are cold and snowy, and much of the developed area, including the Loop Road, closes to vehicles during the snowy months, when the road is used for cross-country skiing and snowshoeing. Spring and fall are milder. In any warm-season visit, sun and heat are the main weather concerns.

Late spring through early fall is the peak season, when the Loop Road and visitor facilities are fully open and trails are accessible; late spring and early fall offer milder temperatures than the peak summer heat on the exposed lava. Summer wildflowers can be a highlight in early season. Because the monument is an International Dark Sky Park, clear nights are excellent for stargazing. Winter transforms the monument into a quiet snow-covered landscape for cross-country skiing and snowshoeing, though the Loop Road is closed to cars, typically from around mid-November until mid-April.

Craters of the Moon protects a young volcanic landscape formed by eruptions along the Great Rift, a system of fissures in south-central Idaho, with the visible lava flows dating from roughly 2,000 to 15,000 years old. The area's stark, lunar-like terrain led to its protection as a national monument and, more recently, its expansion into a national monument and preserve co-managed by the National Park Service and the Bureau of Land Management. The landscape's resemblance to the moon made it a training ground for NASA astronauts preparing for lunar missions. In 2017 the monument was designated an International Dark Sky Park in recognition of its pristine night skies. (The specific original monument establishment date and later expansion date were not verified against a fetched source during research and should be confirmed before publishing.)

Drive the 7-mile Loop Road to reach the monument's main features, and hike its trails, including the climb up Inferno Cone for panoramic views and the Spatter Cone Trail among small volcanic vents. Explore the lava tube caves in the Caves Area, which require a free permit obtained at the visitor center. Camp at the Lava Flow Campground, backpack into the wilderness and preserve, and take advantage of the monument's International Dark Sky Park status for stargazing on clear nights. Birdwatching, photography and ranger programs round out the experience. Bring plenty of water, as the exposed lava fields are hot and shadeless in summer.

Key stops include the visitor center for orientation and cave permits; the North Crater Flow and its trail; Inferno Cone, a steep cinder cone with sweeping summit views; the Spatter Cones; and the Caves Area with its explorable lava tubes. The 7-mile Loop Road links these developed sites. Beyond the road lies the vast Craters of the Moon Wilderness and the surrounding preserve, offering solitude and rugged backcountry across the Great Rift for those with time and preparation.

The monument entrance is directly off U.S. Highway 20/26/93 in south-central Idaho, about 18 miles from the town of Arco to the northeast, with Carey to the west. Most visitors arrive by car as part of a southern or central Idaho road trip; the site is roughly midway between the Sun Valley area and Idaho Falls. There is no public transit to the monument, so a personal or rental vehicle is essential. From the highway, the entrance leads directly to the visitor center and the start of the Loop Road.

The park grounds are open year-round, 24 hours a day, though the visitor center keeps limited hours and the 7-mile Loop Road closes to vehicles in winter (typically by around mid-November, reopening around mid-April). The visitor center generally has extended summer hours (about 8 a.m. to 6 p.m.) from Memorial Day weekend through the third week of September, with shorter hours the rest of the year, and closes in late December before reopening in January; it is also closed on Thanksgiving, Christmas and New Year's Day. Confirm current hours and road status on the NPS site before visiting.

As of research, the National Park Service charged $20 per private vehicle, $15 per motorcycle, and $10 per person on foot or bicycle (ages 16 and up; children under 16 free), each valid for 7 days. A Craters of the Moon annual pass was $35, and the America the Beautiful interagency passes are also accepted. The Lava Flow Campground was $15 per night (or $8 in early/late season without water). No entrance fee is charged when the Loop Road is not fully open to automobiles. Confirm current fees on the NPS site before visiting.

A half day is enough to drive the Loop Road, walk a few short trails such as Inferno Cone, and visit the visitor center. A full day allows time to explore the lava tube caves and take longer hikes, and an overnight stay at the campground lets you add backcountry exploration and stargazing under the monument's dark skies.

Within the monument, the Lava Flow Campground offers first-come or reservable sites for tents and RVs (there are no lodges or hotels inside the park). For indoor lodging, the nearest options are in the small town of Arco, about 18 miles away, with additional and more varied accommodation in larger communities in the wider region such as the Sun Valley area to the west and Idaho Falls to the east. Because on-site options are limited to camping, plan lodging ahead, especially in peak summer.

There are no restaurants within the monument, so bring your own food and plenty of water, especially given the heat on the exposed lava fields. The nearest dining is in the small town of Arco, about 18 miles away, which offers limited casual options. For a wider selection, travelers typically stock up or dine in larger regional towns before or after their visit. Picnicking is a common approach for a day at the monument.

Arco, the nearest town, bills itself as the first city in the world lit by atomic power and is a common stop for gas and food. To the west, the Sun Valley and Ketchum resort area offers mountain recreation and dining, while to the east lies the Idaho Falls region. The broad volcanic and high-desert landscape of the Snake River Plain surrounds the monument, and southern Idaho attractions such as Shoshone Falls near Twin Falls are within a longer drive for a regional road trip.

The monument is reached only by road, via U.S. Highway 20/26/93, and a personal or rental vehicle is required, as there is no public transit to the site. The nearest sizeable airports serving the region are in the broader area, with Idaho Falls to the east and Boise farther west being common gateways for travelers driving in. Fuel and services are limited near the monument, so fill up in towns such as Arco before arriving.

The exposed black lava absorbs heat and offers almost no shade, so carry ample water, wear sun protection and avoid strenuous midday hikes in summer to prevent heat exhaustion. Lava rock is sharp and uneven, so wear sturdy closed-toe footwear and watch your footing. Caving requires a free permit and appropriate gear, including a light and helmet, and visitors should not enter caves alone. In winter, the Loop Road is closed to cars and conditions are cold and snowy. Cell service is limited; for emergencies, dial 911 or contact park staff at 208-527-1300.

Bring plenty of drinking water, sun protection (hat, sunglasses, high-SPF sunscreen) and sturdy closed-toe hiking shoes for the sharp, uneven lava. Pack food, since there are no restaurants on site. For cave exploration, carry a flashlight or headlamp and, ideally, a helmet, and obtain the required free permit at the visitor center. Layers are useful for cool mornings, evenings and shoulder seasons, and warm gear is essential for winter snowshoeing or skiing.

Start at the visitor center to get oriented and to pick up the free permit required for cave exploration. Drive the 7-mile Loop Road early in the day to beat the heat, and tackle exposed hikes like Inferno Cone in the cooler morning hours. Fill your gas tank and stock up on water and food in Arco or another town before arriving, since services near the monument are sparse. Stay after dark if you can, since the International Dark Sky Park designation makes it superb for stargazing. Check the NPS Current Conditions page for Loop Road and visitor-center status, especially outside summer.

For any emergency, dial 911, the nationwide emergency number in the United States. The monument's main phone line is 208-527-1300, per the National Park Service. Cell service can be limited within the monument, so note the visitor-center location and hours in case you need to reach park staff.

Craters of the Moon National Monument & Preserve (National Park Service) - https://www.nps.gov/crmo/index.htm

This section is being updated and will be available shortly.

This section is being updated and will be available shortly.

This section is being updated and will be available shortly.