Castle Mill and Attached Gateway and Gate

Castle Mill, along with its attached gateway and gates, is a late 17th century structure that was largely rebuilt between 1779 and 1782. It features a rendered exterior and a slate roof with end gables, a recessed center, and gabled projecting side wings with slated verges. The building has two storeys plus attics. The central section includes two gabled, slate-hung dormer windows and three-light metal casement windows in wood frames with leaded lights. On the first floor, there is one three-light metal casement window with leaded lights to the left and a stable-type plain boarded door with a hoist to the right. The ground floor has similar windows and doors. Each side wing has one window per floor, with a quatrefoil attic window featuring leaded glazing. The first floor of the left-hand wing has a two-light pointed arch window with intersecting tracery and a single metal casement. The ground floor of the left-hand wing has a four-light mullioned window set in a recessed three-centred arched opening, while the right-hand wing has a plain boarded door in a comparable opening. At the east end, there are twin wooden overshot water wheels. The interior retains mill machinery that is still in working order. A rubble wall with brick dressing extends from the south-east angle of the mill, featuring a pointed arch opening with wrought-iron gates and a lancet opening above, topped with a moulded stone finial.