Castleton is a village in the High Peak district of Derbyshire, England. The village lies within the Peak District at the western end of the Hope Valley on the Peakshole Water, a tributary of the River Noe. The village is situated between the areas known as the Dark Peak (to the north) and the White Peak (to the south). Castleton's population was 649 according to the 2001 census, reducing slightly to 642 at the 2011 Census.