The castle was originally built in 1206, it was a Motte and Bailey, which is still visible to the far left of the present castle. The St. Aulyus lived there for eight years and then erected a stone castle to take the place of the ancient Motte and Bailey structure. This had four floors and a beautiful old fashion stone spiral staircase. Between this and 1800 two other buildings were added, making Killaghy Castle and its appearance what it is today. The original owners were Cromwellian planters by the name of Greene who through marriage, passed ownership of the castle to Despards and then to the Wright family. The castle has been owned by Watson, Fox, Naughton, Bradshaw, and Sherwood families. The present owners are Pat and Maria Collins who run a room and board with an antique Guesthouse with a nature trail, walled garden, a game room, and two tennis courts. The current lands are encircled by a magnificent stone wall and the surrounding land.