The longest continuous lava tube in Oregon, just over a mile of walkable passage under Highway 97 south of Bend, drained by an eruption of Newberry roughly 80,000 years ago. It holds a steady 42 degrees, has sand gardens where fine ash sifted in, and a low “Two Tube Tunnel” where one flow ran over another. PUBLIC (Newberry National Volcanic Monument): fee, seasonal (typically May-Sept), lantern rental on site, and they will decontaminate your gear at the door to slow white-nose syndrome in bats.
Other places on the map within a couple of hours.
