Castletown House is the name of a historic building located in Celbridge, County Kildare, Ireland.
Considered the finest Palladian country house in Ireland, it is an imposing building constructed in 1772 for William Conolly, the Speaker of the Irish House of Commons. The main block was designed by the Italian architect Alessandro Galilei, the wings were added by Edward Lovett Pearce in 1724. The architecture of the building led to the construction of Leinster House and was later used to build the White House in Washington.
The building forms the central part of a 550-acre (2.23 km²) estate, which was sold in 1965 to developers and is now partly state-owned and partly private.
The house and 120 acres (0.49 km²) of the property are under government protection, part of the land is now occupied by modern buildings.
