Like Penmark Castle 2 miles east, East Orchard Castle is a ruined medieval mansion, largely built in the 14th century, on the rim of a valley near the Bristol Channel coastline in the Vale of Glamorgan. The site is usual for being overgrown and unrestored, yet containing extensive remains, since as well as the principal building, a three story accommodation block, it also includes a chapel, hall, barn, dovecote and kitchen, plus lesser remains, all apparently unchanged for several centuries.
The manor is mostly surrounded by a belt of woodland, on the west side of the shallow but relatively steep-sided valley of the River Thaw, 1.5 miles from the coast, near St Athan, with further natural protection provided by a tributary valley a short distance north, however despite some fortified elements the mansion was entirely residential rather than defensive. The mansion was constructed for the Berkerolles family who had been resident in this part of Glamorgan since shortly after the Norman conquest, though much of their history is unclear. An earlier structure on this site was destroyed in 1316 during a revolt led by Welsh leader Llywelyn Bren, but the residence was soon rebuilt. The Berkerolles were subsidiary to the Lords of St Athan, and they occupied the mansion until the early 1400s, when the house passed by marriage to the Stradling family from St Donats, who also endured for several centuries, and carried out various improvements to the buildings. The castle was sold in 1756 but then soon abandoned and partially dismantled, and has been ruinous for over 300 years.
The site is one of the more atmospheric ancient ruins in south Wales, not within sight of any roads or modern developments, and seemingly very little visited. The barn and the dovecote are in the open, along the edge of a field, while the remainder of the buildings are partly hidden by the trees and undergrowth, yet are easy enough to explore, and retain enough architectural detail to give a good idea of what the settlement was like at its peak, in the 16th century.
East Orchard Castle lies quarter of a mile north of the B4265, accessed by an unsigned footpath that follows the course of the original track once used to access the site; this starts with a flight of steps up an embankment, immediately west of the road bridge over the River Thaw. Parking is available close by to the west, at the end of a service road. The path runs between fields and woodland, past two boundaries, to the ruins. The buildings were loosely arranged around two rectangular enclosures, or courtyards; one to the west, slightly higher in elevation, the other to the east, right at the brink of the river valley. The castle is named after the orchards that once existed in the vicinity, and a similar plantation on the west side of St Athan was also protected by a fortified house, West Orchard Castle, of which the only visible trace is an overgrown mound containing masonry rubble.
The first-reached site is a large barn, now just low wall fragments, some of which were incorporated into later farm buildings. Just beyond, to the north, is a dovecote, probably built in the 16th century - a square, sturdy-looking building with a gabled roof, containing compartments for about 200 birds. The dovecote and barn were on opposite sides of the western, outer courtyard, the east side of which is lined by a ground floor hall, latterly also used as a barn, though its relatively elegant windows and doorways indicates that its original purpose was domestic. There is one other building within the upper courtyard, a rectangular single-room structure of unknown purpose. The hall also adjoins the inner courtyard, which has the main manor house on the north side and a chapel to the south; this has lost all its windows and about half of its walls, and about the only recognisable feature is a tapered recess containing a drain, originally the site of the piscina.
The main component of East Orchard Castle is the manor house, which is orientated east-west and centred on a ground floor hall beneath a gable roof. The west end adjoins a two floor service block, with a cross roof, while to the east is a larger, three story range above a basement, also beneath a cross-roof, rising to the same height though taller since the ground slopes downwards; rooms here included a parlour, solar, and other living areas. A north-side annex is flanked by turrets to the east and west, the latter probably once containing a staircase; all of this section was remodelled by the Stradlings during the 16th century. One further ruin, north of the mansion, is a small, square building, the kitchen or bakehouse, which includes the remains of a fireplace.