Penarth Mill is situated in the steep-sided valley of Penarth Brook some 2.5 kilometres west-south-west of Trellech. It is depicted as a working corn mill on all three editions of the 25-inch O. S. map, published in 1881, 1901 and 1921. It is a three-storey building, constructed of roughly-course red sandstone conglomerate under a corrugated iron roof. The internal machinery is thought to be complete, but the breastshot wheel has been removed, leaving a blocked axle hole and an iron water delivery pipe projecting from the mill dam. Water was brought to the mill by a leat 190 metres long.

Information from Cadw Listed Buildings database.
W J Crompton, RCAHMW, 12 May 2011.