Knight's Mill is a small single-storey and attic building, constructed of rubble sandstone under a stone slate roof hipped at the south end. At the rear (west side) is a wheelpit with an overshot waterwheel of composite construction, with cast iron frame and wooden buckets, fed by a wooden sluice box. Water came from a stone weir on the Afon Rhiangoll via a 440 metre long leat which was culverted under cottages at Pont-y-bryn-hurt and the A40 Brecon to Crickhowell road. Inside the mill the pit wheel, wallower and one pair of stones are reputed to survive.

Information from Cadw Listed Buildings database.
W J Crompton, RCAHMW, 13 August 2014.