CASTLETON, a township, in the parish and union of Rochdale, hundred of Salford, S. division of the county of Lancaster; including part of the town of Rochdale, and containing 14,279 inhabitants. This place derives its name from a castle which arose here in Saxon times, and which, it is highly probable, was one of the numerous sacrifices in the conflicts between the Saxons and the Danes; the site is still to be traced by a lofty mound called the Castle-hill, the fosse appearing around it in distinct lines. In Edward II.'s reign, Henry de Lacy possessed the manor of Castleton. On the dissolution of monasteries it was granted to the Radcliffs, of Langley, and subsequently passed by purchase to the Holts, of Stubley, who about 1640 took up their residence at Castleton Hall, and by whom the present edifice was built soon after the Revolution. The Chethams, of Turton, succeeded by purchase to the estate in 1713, since which time it has been successively held by the Winstanleys, Smiths (an opulent mercantile family), and Burdetts. The river Roche, which divides the town of Rochdale, bounds Castleton on the north; and the road to Manchester, the Rochdale canal, and the Manchester and Leeds railway, pass through. A large number of the inhabitants are employed in the woollen and cotton manufactures of the vicinity. The parish church and glebe, on which latter the new part of Rochdale is built, are within the township.