Lava River Cave

At 5,211 feet, the northwest section of Lava River Cave is the longest continuous lava tube in Oregon, and it is the easiest big one in the state to walk into. It sits inside Newberry National Volcanic Monument south of Bend, managed by the Forest Service.

A lava tube is made rather than dissolved. About 80,000 years ago lava poured northwest from a vent believed to be near Mokst Butte, running in an open channel toward the Deschutes River. The surface of that river of rock chilled and hardened into a crust while the molten interior kept flowing, so the flow roofed itself over. When the eruption stopped, the still liquid lava drained away downhill and left the tunnel behind. Later a section of roof fell in, and that collapse is the entrance, opening into both the uphill and downhill halves of the cave. The same flow underlies much of Bend and nearly reaches Redmond, though the vent that fed it has been buried by younger flows since.

Credit for the discovery in 1889 went to a pioneer hunter, but obsidian flakes near the cave make it plain that Native people in central Oregon knew about it long before any settler wrote it down.

One detail catches people out. Roughly 18 inches of rain and snowmelt reach this country each year, and over centuries that water has carried sand down through cracks in the roof and laid it along the floor deep inside, so the far end of the tube is floored in fine sand rather than rock.

The cave holds about 42 degrees Fahrenheit all year and there is no lighting, so bring your own or rent one on site for $7. The 2026 season runs May 15 to September 15, Friday to Monday, 9 a.m. to 4 p.m. with last entry at 2 p.m., and a timed reservation from Recreation.gov is required; parking is $5 a vehicle. The round trip is about 2.2 miles and takes an hour and a half, starting down 55 stairs. No pets, and no clothing or gear that has been in another cave or mine: the Forest Service is keeping white-nose syndrome away from the bats, which is also why the cave closes outside the season and the gated east tube stays shut all year.