Lava Cave Loop

Photo: The Lava Cave Loop winds through the ponderosa pines of the Coconino National Forest west of Flagstaff. | Jeff Kida
Coconino National Forest, Flagstaff
By Kathy Montgomery

In the heat of summer, there’s no better place to take a road trip than Flagstaff, and no better route than this 24.4-mile loop, which winds along shady forest roads past wildflower-filled meadows and includes a short detour to Lava River Cave, Northern Arizona’s natural icebox.

We begin at Forest Road 171, about 10 miles west of Flagstaff. The gravel road is bumpy but wide and straight as it runs through a well-managed ponderosa-pine forest, which occasionally gives way to wide, grassy meadows strewn with volcanic rock.

After a few miles, the road opens to views of Kendrick Peak, one of the larger volcanoes in the San Francisco Volcanic Field. Rising to an elevation of more than 10,000 feet, it’s an impressive sight.

After 7 miles, we turn right onto Forest Road 171B and drive the quarter-mile to the parking area for Lava River Cave. The entrance to the cave is located about 300 yards east of the parking area and is marked by a circle of rocks and a plaque.

The lava-tube cave is three-quarters of a mile long, the longest of its kind in Arizona. Geologists believe it formed in a matter of hours about 700,000 years ago, when lava erupted from a nearby volcanic vent. The tube formed as the top and sides cooled, but the molten river continued to flow through the center.

Because it formed quickly, the cave floor is like a river frozen in time, with ripples and the rocks the lava was carrying suspended in place. The ceiling drips with “lavacicles,” which formed as hot gas shot through the cave shortly after it formed, partially re-melting the lava.

Lumbermen discovered the cave around 1915. Because the temperature inside remains in the 30s and 40s year-round, homesteaders once collected ice from the cave to use for refrigeration.

The tube is slippery, jagged in places and very dark. The U.S. Forest Service advises taking three light sources in case one fails. Headlamps are recommended to keep hands free. The hike is approximately 1.5 miles in and back, and it ranges from a wide, spacious tunnel to a short crab crawl.

Back on FR 171, we could continue straight for another 4 miles to the trailhead for Kendrick Peak. Instead, we turn right after 2 miles onto Forest Road 193. On this road, we catch occasional glimpses of the San Francisco Peaks in the distance and see a small grove of aspens, the first of our drive, growing out of a rocky outcrop.

After 3 miles, we pick up U.S. Route 180, turn right and continue south. This stretch is scattered with stands of aspens, their small leaves glittering like the sequins of a party dress against paper-white legs.

After another 3.3 miles, we turn right onto Forest Road 247. It’s easy to miss, but we find the turnoff just north of Milepost 229, about a mile south of the well-marked turnoff for Forest Road 245.

After a quarter-mile, we turn right onto Forest Road 9008L, a logging road, and creep slowly along the rocky, rutted road, which is not much wider than a hiking trail. Here, the forest feels intimate. It crowds the road, which is littered with pine needles and almost completely shaded. An Abert’s squirrel, with its long, tasseled ears, runs across the road ahead of us.

After 3 miles, we emerge again onto FR 171, turn left and drive the 5 miles back to where we started, with just enough time to head back to Flagstaff for a late lunch.

Tour Guide

Note: Mileages are approximate.

Length: 24.4-mile loop (from Interstate 40)
Directions: From Flagstaff, go west on Interstate 40 for 10 miles to Transwestern Road and Bellemont (Exit 185). Turn right off the freeway, then immediately left onto the frontage road, and continue 0.8 miles to Forest Road 171. Turn right onto FR 171 and continue 7 miles to Forest Road 171B, which leads to Lava River Cave. Back on FR 171, continue another 2 miles to Forest Road 193. Turn right onto FR 193 and continue 3 miles to U.S. Route 180. Turn right onto U.S. 180 and continue 3.3 miles to Forest Road 247. Turn right onto FR 247 and continue 0.3 miles to Forest Road 9008L. Turn right onto FR 9008L and continue 3 miles back to FR 171. Turn left onto FR 171 and continue 5 miles back to the I-40 frontage road.
Vehicle requirements: A high-clearance, four-wheel-drive vehicle is recommended. The route is closed in winter.
Information: Flagstaff Ranger District, 928-526-0866 or