The longest continuous lava tube in the state of Oregon, and one of the largest accessible tubes in the Western United States, is a memorable hiking experience in Newberry National Volcanic Monument.
Over a mile of the cave is open to the public on an interpretative, self-guiding trail. Although it actually extends another 1500 feet, it is closed due to loose and dangerous rocks. Lanterns are available for rent.
The entrance drops quickly from being a hole in the ground to a steep descent over volcanic rocks which have been bridged by stairs. Almost immediately you are on the floor of a large chamber, where stalagmites of ice persist until early June.
This isn’t a narrow little cave. In places the ceiling reaches heights of almost 60 feet and the cave is 50 feet wide. Lava River actually crosses beneath US Highway 97; at that point the ceiling is 50 feet thick.
The floor of the cave appears to be sand, but is really volcanic ash. The constant dripping of water has carved gardens of spires and pinnacles, including volcanic stalactites. These hollow, soda straw shaped tubes were formed by escaping gases.
Lava River Cave was created by a river of molten rock around 80,000 years ago. Archaeological digs around the entrance confirm that it was used by Native Americans, but its official discovery is credited to a stockman and trapper named Leander Dillman who found it in 1889. He used the cave’s cool year round temperature, which hovers between 35 and 40 degrees, as a natural refrigerator to store his game.