Ringhaddy Castle (Tower House), off Ringhaddy Road, Ringhaddy, Killyleagh, Co. Down

Ringhaddy Castle is a ruined 15th-century tower house, partly rebuilt around 1600, located on a narrow neck of land to the south of Castle Island, where the island joins the Ringhaddy peninsula off the west coast of Strangford Lough, approximately three miles southwest of Killinchy.

The building is constructed of rubble and rises to three storeys with a gable level. Almost all of the southwest, west, and north walls have survived, though some sections of the east wall are missing. A full-height square tower is positioned at the southwest corner, with the remains of a stair tower at the northeast corner. A tall chimney stack rises to the west, its upper section harled. Fireplaces remain on the first and second floors of the internal face of the west wall, both now fitted with recently inserted timber lintels and grates partly patched in brick. Window openings of various sizes pierce the upper floors throughout. A second-floor window to the left on the west wall has what appears to be a recently added stone frame. The walls appear to have been harled at an earlier stage, and large sections of stonework have been repointed in recent times. Against the south wall stands the gable of a two-storey outbuilding, probably dating to the mid 19th century. The castle is now in state care.

Ringhaddy Castle is believed to have been built in the 15th century, possibly by a branch of the Savages of The Ards. It appears on various 16th-century maps including Mercator's map of 1595. Around 1600, the castle was captured by Sir Ralph Lane, the Muster Master General, from Bryan McArt and his Hebridean allies. McArt's men demolished the upper floors before retreating, prompting Sir Ralph to appoint Edward Brookes, Seneschal of his country, to rebuild much of the structure and garrison it with fifteen English and thirty Irish soldiers. This work was completed by October 1602. Little is known of the castle's subsequent history. It was in ruins by the 1830s and, as Walter Harris makes no mention of it in his 1744 history of Down, it had presumably been disused for considerably longer.