The family was originally based in a large castle in Maynooth in County Kildare. In later centuries the family owned estates in Waterford with country residence being a Georgian house called Carton House which had replaced the castle in County Kildare. In Dublin, the Earl built a large townhouse residence on the southside of Dublin called Kildare House. When the Earl was awarded a dukedom and became Duke of Leinster, the house was renamed Leinster House. One of its occupants was Lord Edward FitzGerald, who became an icon for Irish nationalism through his involvement with the Irish Rebellion of 1798, which ultimately cost him his life.
Leinster House was sold by the Leinsters in 1815. After nearly a century as the headquarters of the Royal Dublin Society, which held its famed Spring Show and Horse Show in its grounds, Oireachtas Éireann, the two chamber parliament of the new Irish Free State, rented Leinster House in 1922 to be its temporary parliament house. In 1924 it bought the building for parliamentary use. It has remained the parliament house of the Irish Free State (now the Republic of Ireland).
The Dukes of Leinster had by the early 20th century lost all their property and wealth. Their Carton House seat was sold (though one of Ireland's most historic buildings with perfectly preserved 18th century grounds, it was controversially turned into a hotel and golf course in the late 1990s by the current owner in an act condemned by environmentalists), as later on was their other residence in Waterford. The family now live in a smaller property in Ramsden, Oxfordshire.
A controversial claim by the supposed descendants of the 5th Duke (largely debunked by Michael Estorick in 1981) was made and failed, with the Lord Chancellor accepting the claim made by the 9th Duke of Leinster.
Heir Presumptive: Lord John FitzGerald (b. 1952) (The Duke's brother)
The coat of arms of the Dukes of Leinster derives from the legend that John FitzGerald, 1st Earl of Kildare, as a baby in Woodstock Castle, was trapped in a fire when a monkey rescued him. The FitzGeralds then adopted a monkey as their crest (and later supporters) and occasionally use the additional motto Non immemor beneficii (Not forgetful of a helping hand).