Castle Drogo is a country house and mixed-revivalist castle near Drewsteignton, Devon, England. Constructed between 1911 and 1930, it was the last castle to be built in England. The client was Julius Drewe, the hugely successful founder of the Home and Colonial Stores. Drewe chose the site in the belief that it formed part of the lands of his supposed medieval ancestor, Drogo de Teigne. The architect he chose to realise his dream was Edwin Lutyens, then at the height of his career. Lutyens lamented Drewe's determination to have a castle but nevertheless produced one of his finest buildings. The architectural critic Christopher Hussey described the result: "The ultimate justification of Drogo is that it does not pretend to be a castle. It is a castle, as a castle is built, of granite, on a mountain, in the twentieth century".

A castle is a type of fortified structure built during the Middle Ages predominantly by the nobility or royalty and by military orders. Scholars usually consider a castle to be the private fortified residence of a lord or noble. This is distinct from a mansion, palace and villa, whose main purpose was exclusively for pleasance and are not primarily fortresses but may be fortified. Use of the term has varied over time and, sometimes, has also been applied to structures such as hill forts and 19th- and 20th-century homes built to resemble castles. Over the Middle Ages, when genuine castles were built, they took on a great many forms with many different features, although some, such as curtain walls, arrowslits, and portcullises, were commonplace.