Caerhays Castle or Carhayes Castle is a semi-castellated country house built in 1808, 0.5 mi (0.80 km) south of the village centre, St Michael Caerhays, Cornwall, England. It overlooks Porthluney Cove on the English Channel. The garden has a large collection of magnolias.

John Nash was one of the foremost British architects of the Georgian and Regency eras, during which he was responsible for the design, in the neoclassical and picturesque styles, of many important areas of London. His designs were financed by the Prince Regent and by the era's most successful property developer, James Burton. Nash also collaborated extensively with Burton's son, Decimus Burton.