Although most of Strangford Castle was built in the 16th century, it incorporates some work on the ground and first floors from the century before.
It is a simple three-storey stone tower house which once had wonderful views over Strangford’s quays and harbour to Portaferry Castle on the other shore. It is almost square inside with walls that are over one metre thick. The tower rises to ten metres on the north and the building is built with rubble masonry and occasional large boulders. The entrance in the north east wall was protected by a machicolation and the roof has very fine crenellations with pistol-loops. The first floor fireplace contains an oven and the ground floor chamber is lit only by small gun-loops.
Several other tower houses – Audley’s Castle, Portaferry Castle, Kilclief, Old Castleward - are located in this area and all were built to guard the entrance to Strangford Lough and adjacent important anchorage.
Crenellations – regular spaces along the top of the parapet through which arrows or other weaponry could have been shot.
Gun loops – round holes pierced through the walls for defensive purposes.
Machicolation - a floor opening between the supporting corbels of a battlement, through which stones, or other objects, could be dropped on attackers at the base of a defensive wall.