This former O’Shaughnessy fortress, occupied from 1574 to 1729, is a tall 6-story tower with an attic. It has a pair of box machicolations (bartizans) on the north and south corners at the third floor level.
The castle stands in the middle of one of the best preserved bawns in Ireland.
The inner bawn is rectangular with a modest 3-story gatehouse in the northwest curtain and a sharp triangular projection from the southwest curtain which looks like part of a star fortification. Fiddaun is a lofty tower house that is best known for having one of the best-preserved bawns in Ireland. Built during the 16th century for the O’Shaughnessys, it comprises an oblong six-storey tower with vaults over its first and fifth floors. There are square bartizans placed very low down at third-floor level, a peculiarly Irish feature that was brought about by the introduction of firearms, which changed the axis of defence from the vertical to the horizontal.
Located between Lough Doo and Lough Aslaun, the castle was built on a rocky area next to a water-filled channel which partially protected the castle. The original outer bawn, now mostly ruined, enclosed 12 acres, making Fiddaun the largest castle in Ireland.
Most of the O’Shaugnessy estates were forfeited in 1697 when the castle’s owner, Sir William O’Shaughnessy, fled to France. Though only fifteen in 1690, he had fought as a captain in the Jacobite cause and later in exile pursued a brilliant military career, becoming a Mareschal de Camp in 1734. Fiddaul Castle was continuously inhabited by O’Shaughnessys until 1727. Located 8 km SW of Gort, off the Tubber road.