Londonderry House was an aristocratic townhouse situated on Park Lane in the Mayfair district of London, England. The mansion served as the London residence of the Marquesses of Londonderry. It remained their home until 1962. In that year Londonderry House was sold by the Trustees of the 7th Marquess of Londonderry's Will Trusts to a developer who built the "Londonderry Hotel" on the site, not (as is sometimes, erroneously, stated) the Hilton. The Hilton Hotel is on the other side of the street, and had already been opened. COMO Metropolitan London now occupies the site of Londonderry House.