Tristan da Cunha (), colloquially Tristan, is a remote group of volcanic islands in the South Atlantic Ocean. It is one of three constituent parts of the British Overseas Territory of Saint Helena, Ascension and Tristan da Cunha, with its own constitution.
The territory consists of the inhabited island Tristan da Cunha, which has a diameter of roughly 11 kilometres (6.8 mi) and an area of 98 square kilometres (38 sq mi); the wildlife reserves of Gough Island and Inaccessible Island; and the smaller, uninhabited Nightingale Islands. As of October 2018, the main island had 250 permanent inhabitants, who all hold British Overseas Territories citizenship.