The masonry remains of Peterston Castle lie within the grounds of Caehir House to the west and Castleby to the centre. The earliest fragment seems to represent a detached keep, retaining slight hints of twelfth century detail. Other features included a rectangular walled and towered enclosure, approximately 40meast to west by 35m. The court and other towers were later medieval work.

The castle has been progressively destroyed by housing development, and recent Ordnance Survey mapping along with information from the Glamorgan-Gwent Archaeological Trust indicates that only a single fragment remains.

source: RCAHMW 1991, 340-3

J.Wiles, RCAHMW, 28 January 2003