Did you know that present-day Arizona was once covered in flowing molten lava? It’s hard to imagine but in Flagstaff, Arizona we can hike to and explore a remarkable remnant of Arizona’s past at the Lava River Cave Trail.
This fascinating lava cave (also known as a lava tube) offers a unique glimpse into the geological history of the region, dating back thousands of years.
While many might associate volcanoes with places like Hawaii, Japan, or Central America, they have also played a crucial role in forming land all over the world. Nearly 80% of the Earth’s surface was formed by volcanic eruptions.
There are extinct (will never erupt again) and dormant (could erupt again in the future) volcanoes across the country and Arizona is home to many. The Flagstaff area has a 6 million year history of volcanic activity!
You’ll find thousands of extinct volcanoes in the state and three active volcanic fields, the largest being the San Francisco Volcanic Field, where this incredible cave is located.
The Lava River Cave in Flagstaff is the longest known of its kind in Arizona, stretching for over three-quarters of a mile underground. This tube reveals the fascinating natural history of this region while offering a unique hike that is doable for most people.
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How Was The Flagstaff Lava Cave Formed?
This lava cave/tube was formed by an eruption of a now dormant volcano near Michelbach Ranch which is around the Flagstaff area.
As the lava flowed down the volcano, it crossed the landscape in what’s known as a lava river. Just like a river of water, but with lava.
The top surface of the lava river began to cool due to cooler air temperatures above. As the top cooled, it solidified and acted as a “ceiling” that kept the lava hot and flowing underneath. This hot lava continued to flow and began to form a tunnel-like passageway.
Over time, the lava flow ceased and the molten lava within the tube either drained out or cooled and solidified, leaving behind the hollow tube that we can explore today.
Geologists say this lava tube was formed between 650,000 and 700,000 years ago! It has been incredibly well preserved throughout these years.
Now, it is just as important for us to continue to treat this amazing natural wonder with respect and care so future generations can enjoy the cave for many years to come.
Always remember to follow leave no trace principles while exploring the lava cave.
Lava River Cave Trail Info
- 2 miles round trip
- Mostly flat with the exception of an initial steep decline into the cave
- Very rocky
- Pit toilets at the trailhead
Things to Know Before Going into the Lava River Cave
- Have a few different light sources with you- a headlamp would work great here
- Bring layers as the cave will be cold (around 40°F underground)
- Wear close toed shoes for protection from the sharp rocks
- Dogs or any pets are not permitted in the cave
- The cave is tall enough for people to fully stand up and walk through, but there may be a few times you will have to duck
Fees or Permit Required?
No, as of June 2024 there is no fee or cost to hike this trail. Nor do you need any kind of permit.
You can hike the Flagstaff lava cave trail for free at any time of year.
Best Time to Explore the Lava River Cave
Late Spring, Summer & Early Fall
Pretty much any time of year would be a good time to hike into the lava cave but the warmer months are definitely the better time to visit.
Summer is also a wonderful time to hike the cave because it will give you relief from the soaring temperatures of the Flagstaff area. When temperatures are in the 90s or even nearing over 100℉, this lava cave stays a consistent 40℉.
The lava cave itself is open year round but the roads leading you to the trailhead of the cave are closed during the winter months (December-February) due to muddy and snowy conditions.
If you want to go in the cave during winter you will have to hike or ski from Highway 180 to the trailhead which will be a 4 mile trip ONE WAY. So in total, if you go during winter when the forest roads are closed, you’re looking at nearly a 10 mile trek.
We visited in mid-October and it was still open. There was a pretty good amount of people there. It was quite chilly outside in October, but the cave did give us a nice break from the wind.
How to Find the Lava River Cave Trailhead
The trailhead is located about a half hour drive northwest of Flagstaff. The map below shows the drive to the lava tube from downtown Flagstaff.
It’s a little out of the way if you’re just passing by, but it would be totally worth it.
From Flagstaff, you will begin heading north for 14 miles on Highway 180. Then, you will have to make a left turn onto Forest Road 245.
3 miles later you’ll make another left turn onto Forest Service Road 171 and then the trailhead will be on your left after another mile.
These forest roads are not paved but doable for a sedan. You do not need 4 wheel drive.
There is a large parking lot at the trailhead with ample amount of parking spaces so you shouldn’t have any issues there. Weekends are bound to be more crowded.
Starting the Trail
0.15 miles to the Cave
The beginning of the trail takes you through a gorgeous forested area full of ponderosa pine trees. The trail is flat, and composed of fully packed down dirt so it is easy and soft to walk on.
From here you just have a 0.15 mile walk until you stumble upon the entrance to the lava cave.
If you view the trail on AllTrails, you will see that it lists this hike as 0.3 miles. This is only the distance between the parking lot and the cave entrance, so keep that in mind. There is still about ¾ of a mile to go underground until the end of the trail if you choose to go all the way to the end of the lava tube.
Hiking Inside the Lava Cave
As you walk up to the entrance of the cave, you will see a small opening in the Earth surrounded by rocks. It may look small, but I can assure you it is big enough for even tall humans to fit through.
You will have to walk on top of some pretty big rocks to get close to the entrance and some of them can be unstable so you’ll have to be careful.
Once you can peek your head into the entrance, you will see even more rocks to climb over as you descend to the bottom floor of the cave. You will have to take this part carefully too. This may be a challenge for people with physical disabilities because it requires balance as you go down the steep and rocky incline.
Once you’ve made it to the bottom, the ground is significantly easier to walk on. It’s rocky, but you won’t be walking on too many huge unstable rocks. You will still want good shoes for this.
You’ll travel about a half mile or so underground until you come upon a fork in the road. One trail going to the left, and the other to the right. Both of these trails lead to the same place so it doesn’t matter which you pick.
Travel another quarter mile and you’ve made it to the end of the lava tube!
To head back to the beginning of the trail, you’ll just go back the same way you came as this is an out and back trail.
Climbing back out of the cave is easier than going down, but just be careful of any loose rocks.
That concludes this hike guide on the Lava River Cave in Arizona! If you’re road tripping through the southwest I hope this gave you an idea and for something cool to do in Flagstaff. This is definitely one of my top favorite hikes in the area. Thank you so much for reading!
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