Dunsany Castle and Demesne, Medieval castle and national monument in County Meath, Ireland.

Dunsany Castle is an Anglo-Norman castle begun around 1180 for Hugh de Lacy, with four stone towers and walls enclosing a yard; the tower foundations and an old kitchen survive from that phase. It was enlarged in the 18th and 19th centuries and is now more than three times its original size. The long grey stone front has a tall crenellated square tower at the left, two chimneys on the central roofline, and a projecting battlemented tower at the right, behind a dark hedge on a lawn.

Originally constructed around 1180-1181 under Hugh de Lacy, the castle has remained in the same family lineage through the Cusacks and Plunketts, representing one of Ireland's longest continuously inhabited residences.

The demesne church, St. Nicholas of Myra, called "The Abbey", was built in the 1440s on the site of a church of 1305 and is a national monument; family and local graves lie inside and around it, including that of the 20th Lord Dunsany. In 1953 Sybil Connolly showed an early fashion collection at the castle, and the photographs appeared on the cover of Life magazine.

The demesne is reached from the N3 road and from Trim, and is signposted from the Navan Road, Dunshaughlin and Warrenstown near the former Drumree railway station. The main entrance faces a medieval pilgrim cross; its Gothic-ruin look is a later rebuild enclosing a gatehouse lodge. A drystone wall around the estate was largely built as relief work during the Great Famine.

The current owner Randal Plunkett actively implements rewilding conservation efforts across the estate, creating diverse wildlife habitats while maintaining the castle's role as a working historical residence.