Ogmore Castle () is a Grade I listed castle ruin located near the village of Ogmore-by-Sea, south of the town of Bridgend in Glamorgan, South Wales. It is situated on the south bank of the River Ewenny and the east bank of the River Ogmore. Its construction might have begun in 1106. Ogmore was one of three castles built in the area in the early 12th century, the others being Coity Castle and Newcastle Castle. It was in use until the 19th century for a range of purposes, including a court of justice and a prison, but is now a substantial set of remains and a local landmark. It is managed by local authorities. Etymology When John Leland wrote his Itinerary, he referred to this fortress as "Ogor Castelle". The name comes from the nearby river, the River Ogmore (). History Construction of Ogmore Castle might have started around 1106, its foundation predating the Norman conquest. In Caradoc of Llancarfan's The historie of Cambria, now called Wales: a part of the most famous yland of Brytaine, Caradoc wrote that the manor and castle were given to William de Londres, one of the legendary Twelve Knights of Glamorgan, by Robert Fitzhamon, the Norman conqueror of Glamorgan. In 1116, William de Londres was forced to abandon the castle when the Welsh appeared in force. His butler, Arnold, is credited with protecting the castle from the Welsh attack during the absence of William de Londres, and for this, he was knighted Sir Arnold Butler, also receiving the castle and manor of Dunraven as reward. According to the custom of the times, the founding of a religious institution followed the acquisition of power. William de Londres, or his descendant John, built Ewenny Abbey from the castle. Also nearby was a religious place appended to Ogmore Castle by Morris de Londres or his descendant John, in 1141; Ewenny Priory is from Ogmore Castle. When Thomas' heiress married into the Chaworth family of Kidwelly, the lands passed in 1298 to the first Duke of Lancaster, and ownership remains in the hands of the Duchy of Lancaster to this day. Architecture The earthworks were steeply banked and oval in shape, enclosing an area of in length by in width. The inner ward was flat and constructed of timber structures. After completion of the ringwork, the building material was stone. The windows were round-headed with Sutton stone ashlar.