Ogmore Castle overlooks a river crossing of the River Ewenny and was one of three castles built to protect the Normans invaders of Glamorgan from the Welsh they were attempting to conquer. The castle was begun by William de Londres in 1106 as a motte and bailey castle. It was then reconstructed in stone shortly thereafter, and further fortified in the 13th century by a stone curtain wall.
The oblong keep is credited to William’s son, Maurice, and is possibly the oldest Norman keep in Glamorgan. The castle was protected by a deep, rock-cut ditch, which was dry except when the water level of the River Ewenny rose during high tide. At that time, the flow was regulated by an embedded stone wall that blocked rising waters so that the interior of the castle itself did not flood.
Original features still visible today include these banks and ditches and walls as well as a series of ancient stepping stones across the river, which are themselves designated as a scheduled monument.