Ogmore is one of ten significant castles in the Cardiff-Bridgend area of south Wales, south of the M4, built in Norman times to defend the rivers and coastline, in this case by the Londres family, beginning around 1100. The castle occupies a relatively small site right beside the Ewenny River, a short distance upstream of the confluence with the large River Ogmore and a few minute's walk from the sea, at the foot of a wooded plateau (Ogmore Down) to the southeast. The buildings were modified and augmented at various times over the next three centuries, the latest significant addition occurring in the mid 1400s, and today the ruins consist of an inner ward with a hall, keep, tower, gatehouse and cellar, all surrounded by curtain walls, and an outer ward containing a courthouse and a limekiln.
The castle guarded a long-established river ford, along an important travel route between Wales to the west and what was then part of England, to the east. The fort has been owned by the Dukes of Lancaster since the end of the 13th century, and the courthouse was use until the start of the 18th century; ruination of the inner ward began at least a hundred years before. The site is managed by Cadw, and entrance is free. Although comparatively small, the ruins are pretty, and atmospheric, due to the mottled grey and white appearance of the predominantly limestone masonry, the irregular walls, the impressive detail in some of the brickwork, and the setting, in a peaceful, rural position between the hill and the river. The Ewenny is crossed directly opposite the castle by a line of stepping stones, placed here many centuries ago.
Ogmore Castle is 3 miles southwest of Bridgend along the B4254, 1.5 miles before the road reaches the coast at Ogmore-by-Sea. A short track leads to a parking area on the river bank, beside an old, white-washed, thatch-roofed farm house. The carpark adjoins the outer ward of the castle, which contains one building, a roofless courthouse built around 1454, replacing an earlier structure on the same site. At the south corner are the remains of a circular limekiln, of similar age. The outer ward is separated from the main section by a deep, stone-cut ditch, sometimes flooded by the river at high tides, and curving all the way round the south and east sides of the castle. Entry to the inner ward is via a wooden bridge over the ditch, leading to an arched passageway, the surviving part of the gatehouse. The largest component of the castle is the rectangular, thick-walled, Norman keep, originally of three stories (the upper added after the lower two), and one of the oldest castle keeps in Wales. Only one of the four walls remains to any great height (40 feet), and contains several differently-shaped windows plus a fine fireplace, part of a great hall, on the first floor. The northwest corner of the keep adjoins a slender, circular tower, containing latrines, added in the 13th century. On the north side of the inner court is the rectangular outline of another hall, originally two stories, while to the east is the cellar, consisting of several small rooms and a vaulted, arched entrance, once overlaid by other, residential rooms. More foundations can be seen to the south, and all the inner court is enclosed by walls up to 20 feet tall.
Work on Ogmore Castle is thought to have started in 1106, though the site was occupied since before the Norman invasion. The first owner was William de Londres, (died 1126), a knight of Glamorgan, and the initial fort was of wooden construction, surrounded by banks and ditches. William's son Maurice is believed to have built the keep, soon after his father's death, and he is buried in the nearby Ewenny Priory, also established by the Londres family. More structures were added in the 13th century, including the hall, a replacement gatehouse and several residential rooms, plus other buildings in the outer ward of which no trace remains. The castle was not involved in any significant military action, and it changed hands twice towards the end of the 13 century, firstly to the Chaworth family and then to the Dukes of Lancaster. The courthouse in the outer ward is from the 14th century, and was used for many years as an administrative centre for the Lancaster estate.