Crack in the Ground is a volcanic fissure over two miles long and up to 70 feet deep in Lake County Oregon. The length of the fissure can be hiked, as there is an established trail along the fissure's bottom. Normally, fissures like this one are filled in with soil and rock by the processes of erosion and sedimentation, but because Crack in the Ground is located in such an arid region, very little filling has occurred. As a result, Crack in the Ground exists today nearly as it did shortly after its formation. When you get there it is easy to cool off, as the bottom of the crack can be as much as twenty degrees below the surface temperature.

BLM.gov