Lucan House was built on the site of Sarsfield's castle in 1772, by the Rt Hon. Agmondisham Vesey, who was descended from the Sarsfield family. The circular ground floor dining room is said to have been an inspiration for the Oval Office of the White House. The decorative plasterwork was carried out by Michael Stapleton. Over the years, the house passed out of the Vesey family and, since 1942, has been the residence of the Italian ambassador to Ireland. In the grounds of the house is the spa, the waters of which attracted people to the town in previous times.