Castletown House, Celbridge, County Kildare, Ireland, is a Palladian country house built in 1722 for William Conolly, the Speaker of the Irish House of Commons. It formed the centrepiece of a 550-acre (220 ha) estate. Sold to developers in 1965, the estate is now divided between State and private ownership.
On the piano nobile there are a series of ever grander reception rooms typical of the 1720s. The house was entered by ascending a staircase outside before coming into a large Entrance Hall which was graced with Stucco gilding and pictures of the family. To the left is the Dining Room which was made out of two smaller rooms. To the right of the hall was the huge staircase itself. This was made of Portland Stone and is cantilevered.
Straight on is the Green Drawing Room and was also known as the Saloon because of its position in the house. This was the room that the family used to receive their guests in before leaving and (staying on the left hand side of the house) entering the Red Drawing Room.
Another fascinating room, although odd by today's standards, is the Print Room which was decorated by Lady Louisa and friends, following the fashion of the 1760s, with cut-outs of favourite images. This room is on the right side and is thought to be the only surviving example of this in Ireland from this period.
Further on is the State Bedroom, which was never used by royalty as such, but by the various viceroys based in Dublin. In it are chairs which were from Venice.
Another feature of Castletown is the Long Gallery, an 80-foot (24 m) long room decorated in the Pompeian manner by O'Reilly in the 1770s in blue, red and gold.
On William Conolly's death in 1729 the Castletown estate was inherited by his nephew William James Conolly, MP for Ballyshannon. On William James' death in 1754 it passed to his son Tom Conolly whose wife, Lady Louisa (great-granddaughter of Charles II of England and Louise de Keroualle), finished the interior decoration during the 1760s and 1770s. Lady Louisa had grown up in Carton House, a demesne to the north east of Castletown house. Much of the work on the interior was carried out to designs of William Chambers. She also did extensive work on the grounds; the paths through the forest are still in walking condition although, due to anti-joyrider measures, several of the culverts have broken and the pathways are again subject to flooding. The drainage scheme through the woodland is ingenious, creating dry paths for walking on land that is below the watertable. The ha-ha fence is part of this intricate network.
When Tom died in 1803 he left the estate to his wife who on her own death in 1821 bequeathed it to her great-nephew, Edward Michael Pakenham, later the MP for Donegal, on condition he adopted the surname of Conolly. He was succeeded by his eldest son, another Tom Conolly, the eccentric MP for Donegal from 1849 to 1876. 
Tom’s eldest son Thomas inherited Castletown, but after he was killed in 1900 the estate passed to his brother Major Edward Conolly. The Conolly family continued to live in their ancestral house, latterly as the Conolly-Carews, until 1965, when it was sold by The 6th Baron Carew, along with its collections and land, to a Major Wilson for £133,000. Some of the land has been built on, although with some of the estate's features retained amongst the new structures.
The house was bought in 1967 by Desmond Guinness for £93,000 to save it from vandalism, became the flagship of the Irish Georgian Society, and was eventually handed over to the newly-established Castletown Foundation.
The estate was sold on in parts, with 120 acres (0.49 km2) held as curtilage around the house, some small quantities retained privately by Desmond Guinness, the forested Crodaun Woods part sold to what became Coillte and around 25 acres (100,000 m2) acquired over time by Kildare County Council. Most of the core estate remains as woods or green space but a large fraction in the south west was developed as Castletown Estate, controversially approaching the main house closely, and taking in the Walled Garden and the orchard (whose wall remains), which were lost. However, some other features, such as the Gazebo, the Steward's House and a mock temple, were retained, after negotiations between developer Janus Securities and the Irish Georgian Society.
Later still, Castletown was transferred to the Office of Public Works (OPW).
Despite the protection of the house and some estate features, at least one of the outlying features, The Gazebo, was partly demolished, without planning permission, in late 2007. An enforcement notice was served on the developer concerned, and further action is expected.
Former St. Patricks Athletic and current Kerry goalkeeping coach Mick O'Shea is the current caretaker of Castletown House.
Current activities 
Castletown House has opened its doors through OPW to various academic and artistic organisations. The first Arts organisation to take up residency at Castletown House in 2007 was The Performance Corporation, an Irish site-specific theatre company. The company operates an office from the premises as well as running rehearsals for their productions and hosting an annual international cross-artform residency programme, the SPACE Programme.
Access and rights of way 
Access by pedestrians is possible from Celbridge along the former half-mile main drive lined with lime trees. Access by car is from the north beside junction 6 of the N4 / M4 motorway, with a car park near the house. An informal footpath runs along the river Liffey, and a second path runs from the house towards Leixlip, passing the gate lodge designed by Batty Langley.
See also 
- Dr. Paul Caffrey writing on www.irish-architecture.com
- "CONOLLY, Edward Michael (1786-1849), of Castletown, co. Kildare and Cliff, co. Donegal". History of Parliament Online. Retrieved 2012-12-18.
- *Gazebo photos
- Background on Castletown estate and the damage to the Gazebo
- Rights of way detailed in 2006