Newcastle Castle

Newcastle Castle was initially constructed as a ringwork 1106 by William de Londres, one of the legendary Twelve Knights of Glamorgan, as part of the Norman invasion of Wales. William de Londres was a knight loyal to the Norman baron Robert Fitzhamon and the Newcastle defences marked the most western extent of Fitzhamon's lordship. It is one of three castles built by the Normans in the area at the time, the others being Coity Castle and Ogmore Castle. On Lleison's death, thought to be around 1214, the castle came into the ownership of Isabel, Countess of Gloucester, the first wife of King John.

The castle is notable for the high quality of the stonework, especially that of the Norman doorway. This is late 12th century, and was likely constructed at the same time as the high curtain walls and the two square towers which they support. Only the base of the west tower survives, but the south tower has three storeys. This was remodelled for living quarters in the 16th century, when Tudor windows and fireplaces were added.

Newcastle Castle is under the care of Cadw. It is open free of charge throughout the year. A small parking area adjoins the site. A flight of 10 steps between the two main grassland levels restricts access for wheelchair users.