The Manorbier Mill existing now lies to the west of the castle, where an earth dam impounded the waters of a small stream flowing from the north-east. It may be the mill mentioned in 1669, but does not appear to be the mill mentioned by Gerald of Wales (1188), which would seem to have lain south of the castle (see NPRN 310523).

The small corn mill, about 10.5 by 4.5 metres in plan, was built into the earth dam, which has been breached so that water flows away from the mill. The local limestone rubble walls have been restored, but but the building is roofless. There is a later lean-to extension on the south-west side. The internal wheelpit, 2.4 metres wide, is at the north-west end of the building and is thought to have contained an overshot wheel fed by a wooden launder passing through the north-east wall; there is an opening for the tailrace in the south-west wall. The wheel probably drove two pairs of stones, but only fragments have been found.

Information from cadw Listed Buildings database
W J Crompton, RCAHMW, 17 July 2014.

RCAHMW AP955105/52