a visitor with a backpack stands in a large natural tunnel filled with fallen rocks and boulders
A visitor standing in Indian Tunnel

NPS Photo

The number of documented caves within the Monument currently exceeds 500 and more are discovered each year. There are 3 main types of caves found here (listed from most numerous to least): lava tubes, fissure caves, and differential weathering caves.

Lava Tubes

The vast majority of caves found within the Monument are lava tubes. They formed when the cooling exterior of an active lava flow insulated the molten river within allowing it to continue to flow. In this way lava sometimes flowed for many miles underground until the source was cut off or diverted leaving behind an empty space or “cave.” Indian Tunnel is an excellent example of a lava tube. This cave and 3 other lava tubes are easily accessed from the Caves Trail. To explore any of the developed caves, a free cave permit from the visitor center or entrance booth is required before going out.


Caving at Craters

Learn about what it takes to visit the lava tube caves at Craters of the Moon.

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a deep fissure in the ground with a large open chasm in it
Aerial view of King's Bowl.

Fissure Caves

Fissure caves are found within the the deep cracks that make up the Great Rift. Some of these caves are remarkably deep, including one particular fissure that may be passable to a depth of 650 feet (200 meters) from the surface. The King's Bowl area is an excellent place to view the Great Rift but entry into these caves is restricted due to extreme safety hazards within the caves.

a small cave under a slab of reddish rock surrounded by green and yellow shrubs
A small cave formed by differential weathering on Paisley Cone.

NPS Photo

Differential Weathering Caves

These caves were formed when volcanic material was hollowed out by wind, rain and frost. These caves are relatively rare and difficult to find.

Last updated: October 19, 2021

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Contact Info

Mailing Address:

Craters of the Moon National Monument and Preserve
1266 Craters Loop Road
P.O. Box 29

Arco, ID 83213


208 527-1300

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