Castleton is a village in the Derbyshire Peak District, in England. It lies at the western end of the Hope Valley, on the Peakshole Water stream.
Castleton originally grew around the Norman Peveril Castle, and later prospered from lead mining. This created and enlarged local caverns, four of which are now open to the public as Peak Cavern, Blue John Cavern, Speedwell Cavern and Treak Cliff Cavern. A limited supply of Blue John is now mined locally.
The village is surrounded on three sides by hills. Most prominent are Lose Hill and Hollins Cross to the north, and Mam Tor to the west. The road leading east, to Sheffield, used to arrive over Mam Tor, until a landislide swept the road away. Now, all westbound traffic from Castleton must travel up the narrow Winnats Pass.
Castleton attracts large numbers of tourists, some of whom walk the Limestone Way, which runs south from the village. Others gather to watch the ceremony held on Oak Apple Day, when a garland king is paraded around the streets.
Facilities in Castleton include a youth hostel, and several hotels and pubs.