8. Lava River Cave – Oregon
Not all caves are formed from limestone. Lava River Cave, located near Bend, Oregon, was created by flowing molten lava thousands of years ago.
Visitors walk through a mile-long lava tube beneath the forest. The cave is dark, cool, and rugged—headlamps are essential.
It feels less like a decorated cavern and more like stepping into the earth’s volcanic past.
What about Lewis and Clark Caverns in Montana!