A big lava tube in the Horse Ridge country southeast of Bend, named for the Pleistocene animal bones found in it, and one of the largest in the Bend lava-tube system. It is GATED and access is controlled by the Deschutes National Forest to protect hibernating bats, so this is a permit-and-season proposition, not a walk-up. Check with the ranger district before you plan anything.
Oregon
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Other places on the map within a couple of hours.
