Tristan da Cunha, colloquially Tristan, is a remote group of volcanic islands in the south Atlantic Ocean. It is the most remote inhabited archipelago in the world, lying approximately 2,432 km off the coast of Cape Town in South Africa, 2,161 km from Saint Helena and 3,486 km off the coast of the Falkland Islands.
The territory consists of the inhabited island, Tristan da Cunha, which has a diameter of roughly 11 kilometres and an area of 98 square kilometres; the wildlife reserves of Gough Island and Inaccessible Island; and the smaller, uninhabited Nightingale Islands. As of October 2018, the main island has 250 permanent inhabitants, who all carry British Overseas Territories citizenship. There is no airstrip on the main island; the only way of travelling in and out of Tristan is by boat, a six-day trip from South Africa. The other islands are uninhabited, except for the South African personnel of a weather station on Gough Island.
Tristan da Cunha is a British Overseas Territory with its own constitution (as part of the territory of Saint Helena, Ascension and Tristan da Cunha). It uses the Pound Sterling currency for everyday transactions. A major contributor to the island's economy though is the sale of postage stamps on coins issued under the authority of Tristan da Cunha (on some coins abbreviated as TDC).