Newcastle castle was established by 1106, but the present structures date to the 1180's. Its final occupation appears to have been late in the sixteenth century. Ownership passed through the Turberville, Berkerolle and Gamage families and in 1718 it was bought by Samuel Edwin of Llanmihangel Place and later became part of Dunraven estate.
The site is a sub-circular enclosure, describing an irregular polygon, c.42.5m north-south by 38m, defined by ruins of a stone curtain with projecting square towers and a finely finished late Romanesque gate. Raised entirely in ashlar, the outer arch has a rounded head with roll moulding and capitals. The composition frames a recessed segmental inner arch with roll mouldings which alternate with sunken rectangular panels containing strips of pellets. The whole site was originally ditched, except where it rests on steep natural slopes to the east. There are scanty remains of internal buildings.
Source: RCAHMW 1991 Glamorgan III.1a 'the Earlier Castles', 326-36.
Cadw listed buildings database record number 11313.
Kenyon, J.R. and Spurgeon, C.J. 2001. Coity Castle, Ogmore Castle, Newcastle, Cardiff: Cadw: Welsh Historic Monuments.
RCAHMW, 11 March 2008