Backway to Lava River Cave

This backcountry route approaches Lava River Cave through the volcanic badlands north of Flagstaff, following Forest Service roads through ponderosa pine and aspen groves that few tourists ever see. The cave itself formed 700,000 years ago when molten lava created a mile-long underground tube, now accessible to explorers willing to crawl through pitch-black passages with flashlights and warm clothes. Hart Prairie Road (FR 245) connects to lesser-known FR 171 and FR 171B, winding past ancient cinder cones and lava flows that tell the story of the San Francisco Volcanic Field’s explosive past.

High-clearance vehicles handle the maintained forest roads easily, though winter snow can close access from December through March. The cave maintains a constant 35-40°F temperature year-round, so pack layers and multiple light sources for the underground portion. No permits required for cave access, but bring sturdy shoes and gloves for the rocky scrambling inside. Dispersed camping is allowed throughout the forest, making this an excellent base camp for exploring other volcanic features like Sunset Crater. This route combines accessible forest driving with genuine underground adventure in one of Arizona’s most unique geological features.