The Royal Hospital Kilmainham in Kilmainham, Dublin, is one of the finest 17th-century buildings in Ireland.

The hospital was built in 1684 by Sir William Robinson, official State Surveyor General for James Butler, 1st Duke of Ormonde and Lord Lieutenant of Ireland to King Charles II, as a home for retired soldiers of the Irish Army and continued in that use for over 250 years. The style is based on Les Invalides in Paris with a formal facade and a large courtyard. The Royal Hospital Chelsea in Chelsea, London was completed two years later and also has similarities in style. A priory, founded in 1174 by Strongbow, existed on the site until the English closed it down in the Dissolution of the Monasteries in the 1530s.

The Richmond Tower at the end of the formal avenue leading to the Royal Hospital was designed by Francis Johnston, one of the leading architects of the day. This gateway originally stood beside the river Liffey at Bloody Bridge (now Rory O'More Bridge), but had to be moved after the arrival of the railway in 1844 increased traffic congestion. He had placed his personal coat of arms above the arch, concealed by a piece of wood painted to match the stone, his idea being that his arms would be revealed to future generations after the wood became rotten. However, his little trick was uncovered when the gateway was taken down for removal. The coat of arms at present on the gateway is that of the Royal Hospital.

The Royal Hospital Kilmainham graveyards, including Bully's Acre, are 400 metres to the west. A cross-shaft in the former cemetery may be the remains of a boundary cross associated with a ninth-century monastery located at this site.