There’s a cave near Bend that stays a steady 42 degrees no matter how hot it gets outside
Central Oregon’s high desert sun does not mess around in July. About twelve miles south of Bend, though, there’s a mile-long tunnel where the air never budges from a bone-chilling 42 degrees, no matter what the thermometer says up top. That tunnel is Lava River Cave, and it might be the best-kept secret for beating the heat in the entire region.
This is the longest continuous lava tube in Oregon, stretching 5,211 feet beneath the forest floor, and one of the first ever discovered in the state. It formed about 80,000 years ago when a river of molten rock cooled on the outside while the still-liquid core kept draining away, leaving this long stone corridor behind.
Walk far enough in and the entrance light disappears completely — just you, your headlamp, and rock that’s been holding its shape since long before anyone was around to see it form.
Getting inside
Getting into the tube itself means dropping 55 stairs from the entrance down into the dark. From there it’s about 2.2 miles round trip and roughly an hour and a half if you walk the whole thing out and back, though plenty of people turn around well before the far end once the passage narrows and the ceiling starts closing in overhead.
To get there from Bend, head south on Highway 97 to Exit 151, follow the signs through the underpass, and the entrance is about a mile down the road on the left. Coming from La Pine, it’s the same exit from the other direction.
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Before you go
The cave runs on a strict seasonal schedule for 2026: open Friday through Monday, May 15 through September 15, 9 a.m. to 4 p.m., with last entry at 2 p.m. It’s closed Tuesday through Thursday, so plan your Bend weekend accordingly.
Because it draws around 70,000 visitors a season, the Forest Service now requires a timed reservation booked ahead through Recreation.gov — walk-ups aren’t guaranteed a spot. Parking runs $5 per vehicle, or you can use a valid NW Forest Pass at the gate.
Bring warm layers no matter how hot it is outside — 42 degrees feels a lot colder once you’re a quarter mile underground. The Forest Service also asks visitors not to wear or bring in gear used in any other cave or mine, since it can spread a fungal disease deadly to the bats that live here. Closed-toe shoes are a must, two light sources per person are strongly recommended, and pets aren’t allowed inside.
My honest take: skip the flashlight app on your phone and bring an actual headlamp. You want both hands free for the stairs and the uneven floor toward the back of the tube.
More to explore nearby
Lava River Cave sits inside Newberry National Volcanic Monument, the same volcanic landscape responsible for most of Central Oregon’s lava fields and cinder cones. If you want a smaller, more offbeat lava tube in the same region, Skylight Cave near Sisters is worth the detour — it has a natural skylight opening that beams sunlight straight down into the tunnel. And if this has you hooked on Central Oregon, our full guide to the region rounds up plenty more to fill out the trip.
Trip tips: grab a rental car to get out here or lock in your hotel in Bend before the summer crowds book it up. Have you done the full 2.2 miles round trip, or turned back partway like most people do?
Rules and fees change — always confirm current requirements before you go.
