This Subterranean Hike Was One of the Coolest Adventures I’ve Had in Arizona

My Arizona bucket list is long, and I think scrolling on social media is to blame for that. When researching things to do and places to see, I am always amazed at how much the state has to offer. While my bucket list has grown tremendously over the years, some items have held a spot for far too long, just waiting patiently for me to check them off.

One such place I've had at the top of my bucket list for a number of years is the Lava River Cave in Flagstaff. However, upon a visit north with my husband and his kids, I was finally able to check it off! And believe me when I tell you, the subterranean hike to explore the Lava River Cave is among the coolest Arizona adventures anyone can have — and that's in both the literal and figurative sense.

How Did the Lava River Cave Form?

Nearly 700,000 years ago, a volcano vent located in present-day Hart Prairie erupted. Molten rock flowed like a river, forming a crust on its surface as it cooled; however, the hot lava (approximately 2,000 degrees Fahrenheit) continued to flow beneath the crust. Once the last of the lava had emptied, a large and long lava tube (about 3/4 of a mile long) was left behind. It's the longest lava cave in Arizona and an awe-inspiring geological wonder.

It's believed that, in 1915, homesteaders in the area discovered the cave. Inside, it was cold enough for ice to form, and the homesteaders would harvest ice to keep food and drinks cold.

Where Is the Lava River Cave?

Hidden away from both Flagstaff's famous Snowbowl and the attractions along Route 66, the Lava River Cave is surprisingly well-known. People who love unique natural wonders like this lava tube will travel from all over the region just to take a look inside, and those who crave an adventurous experience will head underground and explore it to the end.

So, how do you get to the Lava River Cave located within the vast Coconino National Forest? Coming from Flagstaff, travel north on U.S. 180 for 9 miles. At milepost 230, head west on FR 245, and then continue on FR 171. You'll eventually see a sign for the Lava River Cave and turn left/head south on FR 171B. Once you leave the main road, it takes approximately 15-20 minutes on dirt forest roads to get to the parking lot at the cave, so keep that in mind. Drive slow!

Once you park your car, follow the short trail located near the trailhead sign, which features information about the lava tube and how it was formed. This quick hike leads to an area encircled with a rock wall, and you'll find a makeshift rock staircase leading to the mouth of the cave.

Hiking the Lava River Cave

I was with my husband and his two sons on this hike. Both kids had done the Lava River Cave hike before and were knowledgeable guides for us, members of an older generation. As soon as we climbed down the stairs from the top and entered the cave, the temperature dropped to around 40 degrees, a welcome relief from the 90-degree heat on the surface. It also got dark really fast, so we powered up our headlamps, which became our guiding beacons for the duration of the hike.

The initial descent into the cave was a challenging rock scramble, and some rocks were loose and slippery. While the kids bounded down without issue, my husband and I took our time to ensure we wouldn't slip and fall. Once we arrived at the bottom, the ground was somewhat level for the rest of the way, although there were still some sections with rock scrambles, which were much smaller than the cave's entrance.

With our headlamps and my flashlight, we were able to check out the dark lava floor and walls as we explored. I was mesmerized by walking through such a fascinating piece of geological history. It was almost like being in a natural history museum. As we explored, while watching our footing, we noticed some interesting rocks formed by hardened lava and splashdowns. These are rocks that fell from the ceiling and became embedded in the lava flow 700,000 years ago. Cooling cracks were another fascinating sight, formed as the lava cooled and hardened.

As we trekked on, we came to a fork in the cave, and my husband's eldest son informed us that if we went right, the ceiling would be so low that we might have to crawl. However, going left, we could mostly walk upright, though there are a few areas where the ceiling gets a little too low to allow for upright walking. We chose to go left and eventually reached the terminus of the lava tube. At this point, we were the only hikers at the end of the cave and decided to turn off our lights to get a true sense of how dark it was. Once our lights were off, I realized I had never been in a place that's so dark — it was both eerie and exhilarating.

Pro tip: I advise against doing this hike alone. While AllTrails rates this hike as moderate, there are some tricky sections, such as rock scrambles and low ceilings, that may make you feel uncomfortable. Or, perhaps, you just need a helping hand — after all, it's quite dark even with a source of light, and the ground is uneven throughout the cave. Also, if your phone, headlamp, or flashlight runs out of batteries, your hiking partner may still have power left in theirs to get you both back to the surface.

Additionally, although there are far more people at the beginning of the hike, many turn around due to the difficulty of scrambling down rocks, the darkness, or claustrophobia in sections of the tube with low ceilings. But if you can make it to the end, you and your hiking companions may be the only ones there. You'll also see a stone cairn (a trail marker) someone made, and I think that's pretty cool!

What to Bring With You to Hike the Lava River Cave

There are several items you should bring to ensure your safety and enjoyment during this incredible hike. Here is a list:

• A cell phone with an external battery pack to recharge
• A sweatshirt or jacket and a pair of gloves for the colder temperatures
• A hat or a helmet for areas with low ceilings
• Two or three light sources, including a flashlight and a headlamp
• Bottles of water
• A backpack to carry it all!
• A sturdy pair of hiking boots is a necessity for the uneven ground, rock scrambles, and slippery areas

Have you headed underground to cool off and explore the Lava River Cave in Flagstaff yet? If not, I think this is one of the most extraordinary hikes you can take in Arizona. View the trail map on AllTrails, and don't forget to wear hiking boots for the uneven ground in the cave and bring a headlamp, flashlight, and/or other light source (I suggest taking backups) — you don't want to be left in the dark!

How about another subterranean adventure in Flagstaff? Explore the secret network of underground tunnels downtown on a walking tour. Who knew there were so many fascinating things underground in this Arizona mountain town?