Cilgerran Castle was founded in the early part of the 12th Century (probably around 1108AD) by Gerald of Windsor as an earth and timber "ringwork" fortification. It is believed to be from here that Owain ap Cadwgan, son of the Welsh Prince of Powys, abducted Gerald's wife, Nesta. It is recorded that in 1109AD, a besotted Owain raided "Cenarth Bychan" with fifteen companions and made off with "the Welsh Helen of Troy". This incident sparked a war in Wales, and Owain was eventually killed and Nesta returned to Gerald.

Cilgerran Castle stands on a rock outcrop overlooking the point at which the river Teifi merges with the Plysgog stream. It commands a natural crossing point, and is located low enough down the river to allow access to sea-faring vessels. This would have allowed it to regulate trade both up river and along the coast.

Cilgerran Castle is first mentioned by that name in 1164AD, when it was captured by Lord Rhys. It changed hands a number of times over the following decades, eventually falling under the hand of William Marshal the younger, Earl of Pembroke, in 1223AD. He rebuilt the castle in stone, defending its vulnerable side with a twin curtain wall and distinctive round towers. Within 50 years however, Cilgerran Castle had fallen into decay. It was brought back into service in 1377AD by Edward III, who undertook repairs in the face of a threatened French invasion.

The castle saw action in 1405AD, when it was attacked by Owain Glyndwr's forces and heavily damaged. This was the last time it was to see military action. Eventually, Henry VII granted the castle to the Vaughan family who used it as a domestic dwelling until they relocated to a newly built house in the early 17th Century. Subsequently, Cilgerran Castle fell into ruin.

Today, Cilgerran Castle is tucked away in a hidden corner of a quiet Welsh village. Its position above the wooded gorge of the river Teifi makes for a particularly scenic and pleasant location. The surrounding ditches and the remains of the gatehouse give a good impression of the castle's defensive arrangements. Despite it's ruinous condition, the surviving walls and imposing round towers make it a visually striking and unusual site to visit.