Cooling Off in Flagstaff’s Lava River Cave

The Lava River Cave is about 30 minutes outside of Flagstaff, Arizona. The cave was formed about 700,000 years ago, when molten lava erupted out of nearby Harts Prairie. It was found in 1915 by some lumberman. Nowadays, the Lava River Cave is an easy hike and a great place to escape the summer heat since it stays a cold 40°F (5°C).
Flagstaff Lava River Tube

Flagstaff Lava River Cave Entrance

It is believed the cave was formed when molten lava erupted from a lava vent near Hart Prairie. The top, bottom, and sides of the cave solidified while lava continued to flow, giving the cave its present day shape. The cave is about .75 of a mile long and ranges in height from 30 feet to just 2 or 3 feet.

Lava River Cave is really just a long tunnel, so there’s no worry of getting lost. But remember to bring at least two light sources though, because it is completely dark with no artificial light. I would recommend a headlamp and separate flashlight. There can be low ceilings in the cave so be sure to watch your head.

Lava River Tube Cave, Flagstaff

Inside the Lava River Cave

Last, please be respectful of the cave as they have fragile environments and be sure to pack out any trash you may have brought it. There were problems in the past with litter and graffiti and the major clean up effort was organized in 1991 to pack out all the trash.

Know Before You Go:

  • There is no entrance fees for the cave; it’s open to the public year round. 
  • Location: About 14 miles north of Flagstaff on paved highways and graveled forest roads.
  • GPS Coordinates: N35° 20′ 32.1714″, W111° 50′ 8.196″
  • Access: Drive 9 miles north of Flagstaff on US 180 and turn left on FR 245. Continue 3 miles to FR171 and turn left. About a mile later there will be a turnoff for FR 171B which takes you a short distance to the parking area for the Lava River Cave.
  • Note: Though the Lava River Cave is open year round, FR 245 and/or FR171 may be closed in the winter for resource protection. In those cases, you will need to hike, ski or snowshoe to the cave.
Map to the Lava River Cave in Flagstaff

Lava River Cave Map

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Cooling Off in Flagstaff’s Lava River Cave


  1. Roberta Loufek says

    Nice post – I live in Flagstaff and the lava tube as it’s sometimes called is a natural wonder. You are so right about the advice to bring at least two light sources; there’s absolutely no light in there. Knee pads can be a good thing as well, especially for taller folks since it gets lower the further you go. This is a great place to bring kids to learn a little about geology.

  2. says

    My brother and nephew live in Flagstaff. I’ll have to ask them if they know about this place. However, I doubt that I’ll be going inside this cave. Not much for long tunnels with no natural light. :)

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