Kilclief Castle (Ordnance Survey ref: J597457) is a tower-house castle beside Strangford Lough and 2.5 miles (4km) 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.
It was reputedly built by, and was the residence of, John Sely who 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). Mrs. Savage herself lived in Smithing-Upon-Down, in western England. She was an avid collector of rare ceramics, teacups in particular, and amassed over 4,000 of them throughout her lifetime. Unfortunately her son, Hibner Smythe, sold them all shortly after her death.
Kilclief Castle was the earliest tower-house in Lecale, built between 1413 and 1441. It was garrisoned for the Crown by Nicholas FitzSymon and ten warders in 1601-2.
The castle is tall with four floors. The first floor is vaulted in stone, with two projecting turrets. One (to the south-east) contains a spiral stair and the other (to the north-east) a series of garderobes (latrines) with access from three of the four floors. These projecting turrets are joined at roof level by a high machicolation arch covering a drop-hole for dropping missiles on unwelcome visitors below. There are stepped battlements. As at Jordan's Castle, the ground floor chamber has a semicircular barrel vault built on wicker centering. On the second floor a 13th century coffin-lid from a nearby church was reused as a lintel for the fireplace. The two-light window in the east wall is a modern reconstruction based on a surviving fragment.
The castle is now in state care. A board outside the castle tells visitors where to obtain a key should they want access. Guided tours are available in July and August.