As of the 13th century, the lands on which Killiney Castle was later built, was reputedly under the control of the
Talbots of Malahide.
18th century development Colonel John Malpas constructed Mount Malpas, now known as Killiney Castle, in 1740. An advertisement in Falkiner's
Dublin Journal of 1752 suggests that Malpas may have rented the castle in its early years: "Roxborough, formerly called Mount Malpas, containing 150 acres of land enclosed by a stone wall and a new well-furnished house of six rooms and two large closets on a floor with offices". The original Mount Malpas was a Georgian mansion, with two-storeys over a basement. By the mid-18th century the estate was known as "Loftus Hill" and associated with
Henry Loftus (MP for Bannow in
County Wexford and later Viscount of Ely).
Warren Era (1834-1872) By the mid-19th century, the estate was associated with Robert Warren, a solicitor and developer who had made a fortune selling land to the Dublin and Bray Railway. Warren's home, Killiney House, was renamed Killiney Castle after it was given crenellations. These works were completed and are attributed by several sources, including the
Dictionary of Irish Architects, to Warren's relative, architect Sandham Symes. The works included the installation of
castellations, fake medieval corner towers, turrets, battlements and a Gothic porch. A
Church of Ireland church, dedicated to the Holy Trinity, was also built on the
demesne in 1859. Warren had influence with the railway company since he owned the coastal lands along the rail route from Dalkey to Bray and beyond. After some negotiation, a tunnel was built, allowing the line to open. As part of the agreement,
Obelisk Hill Halt was built on Warren's land, increasing the value of his holdings and quickening the rate of local development. The Jesuits occupied the house between 1877 and 1880. The building was requisitioned and used as billets for Irish Army during
The Emergency (1939–1945). the castle was converted and opened as a hotel in the early 1970s. == Demesne ==