CASTLETON, a village of north Derbyshire, England, Dom. N.E. of Buxton. Pop. of parish (1921) 646. Lying at an elevation of about 600ft., it is surrounded on the north, west and south by steep hills rising to a height of from 1,400 to D,7ooft. above sea-level. The district is celebrated for its caves and mines and for the ruined Castle of the Peak, placed on a cliff immediately above the village. The Peak Cavern or Devil's Hole, penetrating this cliff, is the most magnificent in Derbyshire. For many generations the entrance to this cave has served as a work shop, held free of rent, to families employed in rope and twine making. Speedwell Cavern is not far distant, at the entrance to the fine pass of Winnats, by which Castleton and the Vale of Hope are approached from the west. Among several other caves is that known as the Blue John Mine, from the decorative fluorspar called "Blue John" which is obtained here. The church of St. Edmund, Castleton, retains a fine Norman chancel arch, and the vestry contains a valuable library. The Castle of the Peak, or Peveril Castle, is famous through Sir Walter Scott's novel Peveril of the Peak. Early earthworks, extending from below the castle in a semi-circle, can still in great part be traced. Before the Conquest the site was held by Gernebern and Hundinc, and was granted by the Conqueror to William Peverell, by whom the castle was built. In 1216 William Ferrers, earl of Derby, took it from the rebellious barons, and was made governor by Henry III., who in 1223 granted a charter for a weekly market at the town. In 1328 the castle was given to John of Gaunt on his marriage with Blanche of Lancaster, and thus became part of the duchy of Lancaster. The castle has often been used as a prison, and from its position was almost impregnable.