Castle Mill is a late eighteenth/early nineteenth century, two-storey water-mill built of rubble stone with a gabled slate roof. The east side is built into a bank which gives direct access to the milling floor. The mill leat enters through the rear wall to an internal wheel pit at tyhe south end of the building, but the overshot wheel and all machinery have been removed. The north end has a lower level cart entrance with a flat timber lintel and half-glazed double doors. On the west side is a single storey cart shed with two pairs of double doors.
RCAHMW, 29/09/2003.