Hidden · Newberry National Volcanic Monument, Bend, United States
Lava River Cave
A lava tube south of Bend where molten rock once ran underground, now a cold, dark walk past ice, glazed walls and a sand garden.
A river of lava that drained and left a tunnel.
Lava River Cave is 12 miles south of Bend, Oregon, on the east side of Highway 97. It is part of Newberry National Volcanic Monument, managed by the U.S. Forest Service within the Deschutes National Forest. The northwest section is 5,211 feet long and is the longest continuous lava tube in Oregon.
The cave formed about 80,000 years ago, when lava flowed northwest from a volcanic vent toward the Deschutes River. The flow began as an open channel of lava. A crust hardened over the top and roofed it in, and when the eruption stopped the lava drained out and left the tunnel. A section of the roof later collapsed, and that opening is the entrance to both the uphill and downhill parts of the cave. Sand carried in by seeping water has plugged the far end, so no one knows how far the cave really goes.
Archaeologists conclude that Native Americans knew the cave long before settlers arrived, because obsidian flakes lie near it. The first recorded discovery is credited to a settler hunting in 1889. The name comes from a 1923 geology study, which also produced the first map. A lumber company donated the land around the entrance to the State of Oregon in 1926, the Forest Service acquired the cave in 1981, and it joined the national monument in 1990.
Ice, echoes and a sand garden.
The entrance is a large hole in the ground. A trail drops over a pile of fallen rocks, the Collapsed Corridor, and visitors go down 126 steps with handrails. At the bottom is a cool chamber where winter ice fills cracks in the floor and ice stalactites can cling to the ceiling until June.
Farther in, the ceiling rises to 58 feet and the cave is 50 feet wide. This is Echo Hall, whose smooth, symmetrical walls carry sound and still show the shelves left by the lava current. Around 1,500 feet in, the tunnel passes under Highway 97, marked by a small sign post. Beyond it, in Low Bridge Lane, the ceiling drops below six feet and the walls have a shiny glaze where they melted again. There are also small volcanic stalactites called lavacicles.
About 3,000 feet from the entrance is the Sand Garden, where fine volcanic ash from the eruption of Mount Mazama 6,600 years ago was carried in by dripping water and carved into spires. It takes hundreds of years to form, so the Forest Service has fenced it off. Past it the ceiling keeps dropping, and the last stretch means crawling on hands and knees. The section that runs southeast from the entrance is not open to the public because of loose rocks in the ceiling.
The cave and its entrance.
Practical notes.
Before you go.
How long is Lava River Cave?
The northwest section is 5,211 feet (1,588 m) long, the longest continuous lava tube in Oregon. The southeast section, 1,560 feet long, is not open to the public.
How cold is it inside?
The cave stays at 42 degrees Fahrenheit (5.6 degrees Celsius) year-round, so the Forest Service strongly recommends a warm jacket.
How do you get in?
You go down 126 steps with handrails over a pile of fallen rocks, then walk into the tube. The deepest stretch past the Sand Garden requires crawling on hands and knees.
What light do you need?
A battery light that gives reliable light for at least an hour has been the guidance, and glass globes, kerosene and white gas are not allowed. Lanterns have been rented at the visitor center above the cave. Check the Forest Service for current rules.
Around Bend
Walking tours, day trips and experiences around this area, on GetYourGuide.