Lyons Demesne, Country estate in County Kildare, Ireland

Lyons Demesne is a Georgian country house and estate at Lyons Hill, County Kildare, Ireland, completed in 1797 to designs by architect Oliver Grace and set in 600 acres. The Directoire-style house has a portico incorporating three columns from the ruins of Nero's Golden House in Rome, and the grounds hold a 22-acre spring-fed, stocked lake, stables, stud farm facilities and natural gallops.

The mansion was built in the late 1700s for Nicholas Lawless after he acquired the land from the Aylmer family. In the 20th century the estate passed through several owners before coming to University College Dublin, which now uses it as a research and teaching campus.

The village part of the estate was sold to the Cliff Collection in 2016 and became the hotel Cliff at Lyons; its restaurant Aimsir earned two Michelin stars in 2019. The house itself was bought by Ryanair businessman Tony Ryan in 1996, who spent about €100 million renovating it before bequeathing it to his sons.

The estate is set in open countryside and is most easily reached by car, as public transport options nearby are limited. Because part of the grounds serves as a working campus, it is worth checking in advance which areas are open to outside visitors.

Three columns from the ruins of Nero's Golden House in Rome were shipped to Lyons and set into the portico; a fourth shipment of classical art sank off Wicklow. A statue of Venus dug up at Ostia also came with them. The columns are among three shiploads of Italian antiquities bought by Valentine Lawless, 2nd Baron Cloncurry, who spent £200,000 on the house.