Clandon Park House is an early 18th-century grade I listed Palladian mansion in West Clandon, near Guildford in Surrey.It stands in the south east corner of Clandon Park, a 220-hectare agricultural parkland estate which has been the seat of the Earls of Onslow for over two centuries. The house and gardens were given to the National Trust in 1956, but the park remains in private ownership. Some of the house's contents have also been acquired by the Trust in lieu of estate duty.Construction of the house, designed by Italian architect Giacomo Leoni, began about 1730, and the interiors were finished by continental sculptors and plasterers in the 1740s. It replaced an Elizabethan house. The park was landscaped by Lancelot 'Capability' Brown in 1781, and there are two formal gardens on either side of the house. Nearby is a Māori meeting house, one of only four outside New Zealand, that was brought to England in the late 19th century. After being transferred to the National Trust, the house underwent restoration before it was opened to the public, and later became a wedding venue and filming location for period dramas.
The house was badly damaged by fire in April 2015, probably caused by an electrical fault in the basement, leaving it "essentially a shell", with only one room, the Speaker's Parlour, intact. Thousands of historic artefacts, paintings, and items of furniture were lost in what has been described as a national tragedy. In January 2016, the National Trust announced that some of the principal rooms on the ground floor would be fully restored to the original 18th-century designs, and upper floors will be used for exhibitions and events.