The British Antarctic Territory is the oldest territorial claim to a part of the continent. It includes all the lands and islands in a wedge extending from the South Pole to 60° S latitude between longitudes 20° W and 80° W. It is administered by the Foreign and Commonwealth Office as an Overseas Dependent Territory. There is no indigenous population, but the British Antarctic Survey has three research stations there and the Royal Navy maintains an ice patrol vessel, HMS Endurance , in the area during the austral summer. The Territory has it's own legal system and legal and postal administrations. Revenue from income tax and the sale of postage stamps means that it is financially self sufficient.

Although the United Kingdom claims sovereignty over this region, there are overlapping claims by Argentina and Chile. Under the terms of the Antarctic Treaty, all territorial claims remain frozen, allowing the whole of Antarctica to be used as a continent for peace and science.

The Antarctic Peninsula was the first part of the mainland of Antarctica to be sighted by explorers. In 1820, Smith, Palmer and Bellingshausen all sighted the Antarctic Peninsula. Many expeditions in the nineteenth and twentieth centuries visited the Antarctic Peninsula and the South Shetland Islands, and the region contains many sites of historic interest. British Antarctic Territory has a great wealth of marine life, including large breeding colonies of penguins and seals, which attracted the first sailors to the region in pursuit of fur and seal-oil. British Antarctic Territory includes a wide range of landscapes, from the spectacular mountains and islands of the Antarctic Peninsula, to the smooth plains of the ice shelves and ice caps.