British and Irish country house contents auctions are usually held on site at the country house, and have been used to raise funds for their owners, usually before selling the house and estate. Such auctions include the sale of high quality antique paintings, furniture, objets d'art, tapestries, books, and other household items.
Country house contents auctions have been held formally since at least the mid 18th century, when dedicated auction houses were founded. The main auctioneers coordinating these sales today are Sotheby's, Christie's and Bonhams, with other auctions conducted by Lawrence's. A high quality auction catalogue is also published, giving details and photographs of the lots, including provenance, technical descriptions and estimated sale price ranges. These catalogues can also become collectables in their own right.
The largest on-site contents auction to date, by proceeds value, is Viscount Leverhulme's Thornton Manor in the Wirral, raising over £9.5 million in 2001. However, in present-day values, the largest is still probably the Earl of Rosebery's Mentmore Towers in Buckinghamshire, which generated over £6 million in 1977. The Wentworth Woodhouse £15 million auction in 1998 is excluded because the items had not been in situ in the house prior to the auction, and they were not auctioned at the house, but rather in Christie’s London auction rooms. However, all these figures are occasionally eclipsed by the one-off sale of a special painting or drawing (not listed here), such as the private sale of Castle Howard's Sir Joshua Reynolds "Portrait of Omai" to the Tate Britain for £12.5 million in March 2003, and Alnwick Castle's sale of Raphael's "Madonna of the Pinks" to the National Gallery, London for £35 million in 2004. Additionally, there can be the sale of paintings no longer in situ, but on loan to galleries, such as the 7th Duke of Sutherland of Mertoun House who sold Titian’s Diana and Actaeon for £50m in 2008 and Diana and Callisto for £45m in 2012 to the British and Scottish National Galleries, both originally hanging in Bridgewater House from 1854 until 1939.
Below is a list, in reverse chronology, of the most significant country house auctions, including those in Scotland, Wales and Ireland (if not specifically stated, the house is in England). Also listed are the number of days the auction took to complete (in brackets), the name of the auction house, the gross auction proceeds and the total number of sale lots, if the information is available.