Craters of the Moon National Monument and PreserveAbout Craters of the Moon National Monument and Preserve
Craters of the Moon National Monument and Preserve is a protected area in central Idaho that preserves a large basaltic lava field, cinder cones and fissure eruptions. The site illustrates relatively recent volcanic activity in the Snake River Plain and contains numerous lava flows and tube caves.
Extensive lava fields, spatter cones and lava tubes, plus short interpretive trails and a visitor center with geology exhibits. The landscape is unusual in the continental United States for its well-preserved pahoehoe and ʻaʻā flow textures and volcanic landforms.
The monument was established in 1924 and was later expanded with additional federal protections to create a preserve that covers a broader area of volcanic terrain. Interpretive programs explain the volcanic history and access requirements for caves and backcountry areas.
The site lies in central Idaho near the towns of Arco and Carey, accessed from US Highway 20 and serving as a gateway for visitors traveling through the Snake River Plain.
- Federal protection: Designated a national monument in 1924 and expanded to include a national preserve designation in 2000, protecting volcanic features and surrounding lands.
What to See#
- Visitor Center: The visitor center provides orientation, exhibits about volcanic processes and maps for the park’s trails and cave access points, and is the usual starting point for the auto loop and hikes.
- Loop road and trails: A paved loop road with pullouts and short trails crosses the main lava fields and provides access to interpretive trails and viewpoints over cinder cones and pahoehoe flows.
- Lava tube caves: Several lava tube caves and tunnels formed by past flows are accessible from marked entrances; visitors are advised to carry lights and follow posted safety rules when entering caves.
Best Time to Visit Craters of the Moon National Monument and Preserve
Best late spring through early fall when roads and trails are most reliably open and daytime temperatures are comfortable.
Weather & Climate near Craters of the Moon National Monument and Preserve
Craters of the Moon National Monument and Preserve's climate is classified as Cold Semi-Arid - Cold Semi-Arid climate with mild summers (peaking in August) and freezing winters (coldest in January). Temperatures range from -13°C to 30°C. Semi-arid with limited rainfall.
| Month | Comfort | Temp | Feels | Rain | Sky | Humidity | Wind | UV | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | - | -13° - -2° | -13° | 46 mm | - | - | 3.2 m/s | - | - |
| February | - | -11° - 1° | -10° | 34 mm | - | - | 3.3 m/s | - | - |
| March | - | -7° - 6° | -5° | 32 mm | - | - | 3.6 m/s | - | - |
| April | - | -3° - 12° | 2° | 25 mm | - | - | 3.8 m/s | - | - |
| May | - | 2° - 18° | 8° | 38 mm | - | - | 3.7 m/s | - | - |
| June | - | 6° - 23° | 15° | 32 mm | - | - | 3.6 m/s | - | - |
| July | - | 10° - 29° | 20° | 19 mm | - | - | 3.3 m/s | - | - |
| August | - | 10° - 30° | 20° | 21 mm | - | - | 3.2 m/s | - | - |
| September | - | 5° - 24° | 15° | 22 mm | - | - | 3.1 m/s | - | - |
| October | - | -1° - 17° | 6° | 18 mm | - | - | 3.3 m/s | - | - |
| November | - | -6° - 6° | -4° | 37 mm | - | - | 3.3 m/s | - | - |
| December | - | -12° - -1° | -12° | 45 mm | - | - | 3.2 m/s | - | - |
How to Get to Craters of the Moon National Monument and Preserve
Craters of the Moon National Monument and Preserve lies along US‑20 in south‑central Idaho near the towns of Arco and Carey; the park and visitor center are reached directly from US‑20/26/93. The site is typically accessed by car - expect a rural highway drive from regional centers (for example, allow roughly 1.5-2 hours of driving from the Idaho Falls area depending on route and conditions). Check the monument’s official site for current road conditions and directions to the visitor center and trailheads.
Tips for Visiting Craters of the Moon National Monument and Preserve
- Plan an early-morning visit to the lava fields to avoid midday heat and to have clearer views over the landscape; afternoon light can be harsh on the dark lava surfaces.
- Check the park's visitor center hours and road conditions before you arrive-services are limited nearby and some trailheads are seasonal or have primitive access.
- Stay for dusk or a night if you can: Craters of the Moon is recognized for dark-sky viewing, and stargazing programs or self-guided astronomy are exceptional when scheduled.