Peak Cavern or locally know as the Devils Arse is a large cave in the Peak District village of Castleton. It has been in use since the 9th century.

The cave has been used as a rope making factory for at least 400 years, making rope for the local lead mines. Some remains of this still exists and the workers houses lined the entrance.

The cave lies under Peveril Castle. Deep into the cliff is the caverns entrance chamber, the largest natural cave entrance in the UK. As you go deeper into the cavern you will hear the acoustics of the Orchestra Gallery in the Great Cave, see a constant cascade of water at Roger Rains House, pass through Plutos Dining Room into the Devil's Cellar where you can hear the source of the river Styx. The cave rock is made up from ancient coral rock.