Coordinates: 54°19′41″N 5°33′14″W / 54.328°N 5.554°W
Kilclief Castle (Irish: Caislean Cill Cléithe) (Ordnance Survey ref: J597457) is a tower-house castle beside Strangford Lough and 2.5 miles (4 km) south of the village of Strangford, County Down, Northern Ireland. Kilclief is a hamlet of historical value on the Strangford to Ardglass road. This kind of tower-house is sometimes called the gatehouse type, because of its similarity to a castle gatehouse. It is among the oldest tower houses in Lecale. Kilclief Castle tower house is a State Care Historic Monument in the townland of Kilclief, in Down District Council area, at grid ref: J5972 4575.
Kilclief Castle was the earliest tower-house in Lecale, and was built between 1412 and 1441.
Kilclief Castle was originally occupied by John Sely, who is said to have built the castle. John Sely was Bishop of Down from 1429 to 1443, when he was ejected and deprived of his offices for living there with Lettice Whailey Savage, a married woman. Lettice Savage also lived in Smithing-Upon-Down, and was an avid collector of rare ceramics