Touring Oregon's Longest Lava Tube | Oregon Geology [CC]

Lava River Cave, just south of Bend, is Oregon's longest lava cave. Over 5,000 feet from daylight to the end, it is an easy cave to explore and the Deschutes National Forest maintains the cave for public visitation (there is a small fee to visit). This cave houses numerous original features – that is, they are largely unchanged from when Newberry Volcano produced this lava flow ~75,000 years ago. One stretch has two levels, though the upper is inaccessible. This happens because lava can be present for a long time in a lava tube and it sometimes would crust over and divide the tube in half. Ergo, multiple levels. This is a fantastic lava tube to visit if you've never been to one before.