flagstaff lava river cave (lave tube)

Lava River Cave is a lava tube cave in northern Arizona's Coconino National Forest. At approximately 0.75-mile long, it is the longest cave of this kind known in Arizona. The cave was discovered by some lumbermen in 1915.
Address: Forest Road 171, Flagstaff, AZ 86001
Phone: (928) 526-0866
Management: United States Forest Service

DIRECTIONS: From Flagstaff, go northwest on US 180 to mile marker 230 (9 miles). Turn left (W) on FR 245 and follow it 3.6 miles to its intersection with FR 171. Turn left (S) on FR 171 and go 1.0 miles to FR 171B. Follow this .25 miles until its end. The cave entrance is 300 yards east of the end of the road. Look for a large circle of rocks that mark the cave entrance.

*Important for your safety* This hike will take you 3/4 (1.5 mi round trip) of a mile underground. Take 2 sources of light per person, one for backup in case the other fails.

The cave floor is very rocky and uneven, sturdy shoes/boots are a good idea and the temperatures of the cave range between 35 and 45 degrees summer and winter so dress appropriatly.
This very unusual hike will take you down a 700,000 year old lava tube discovered by lumbermen around 1915.