'This I believe the only house in Ireland to which the term palace can be applied. '
Richard Twiss, 1775
Castletown is Ireland's largest and earliest Palladian style house. Built between 1722 and 1729 for William Conolly, Speaker of the Irish House of Commons and the wealthiest commoner in Ireland. The façade was almost certainly designed by the Italian architect, Alessandro Galilei, while the Irish architect Sir Edward Lovett Pearce added the wings.
The house remained in the hands of the Speaker's descendants until 1965 when the house was purchased by a property developer Major Wilson. Fortunately the house was saved in 1967 when along with 120 acres of the demesne lands it was purchased by the Hon. Desmond Guinness, founder of the Irish Georgian Society for £93,000. The house was opened to the public in the same year and restoration work began, funded by the Irish Georgian Society and private benefactors. In 1979 care of the house passed to the Castletown Foundation, a charitable trust which was established to own, maintain and to continue the restoration of the house.
In 1994 the house with the exception of the contents, was transferred to State care and it is now managed by the Office of Public Works. The transfer to State ownership has paved the way for a major programme of restoration and conservation work of the house and demesne lands. Through restoration, conservation, acquisition of parkland and development of visitor facilities, the long term objective is to preserve for future generations one of the most important houses in Ireland and one of significance in terms of European architectural heritage.