Approximate location — plotted from published sources, not a site visit, and not a guarantee of access.
Lava River Cave is a roughly three-quarter-mile lava tube on the Flagstaff Ranger District, formed about 700,000 years ago by flows from Hart Prairie. A short trail from the parking area enters the dark tube, which stays near freezing year-round. Forest Roads 245 and 171 give summer vehicle access and often close under winter snow.