Tristan da Cunha is an island, an island group, and a colony of Great Britain in the South Atlantic Ocean about midway between southern Africa and South America. It comprises six small islands: Tristan da Cunha, Inaccessible, Nightingale, Middle, Stoltenhoff, and Gough. The group is a dependency of the British colony of St. Helena. Inaccessible, Nightingale, Middle, and Stoltenhoff are uninhabited, while a weather station is manned on Gough Island.

Island Tristan da Cunha is the largest and northernmost of the group.  It has an area of 38 square miles (98 square km).  It is roughly circular, with a coastline of 21 miles (35 km) and a central volcanic cone (6,760 feet [2,060 m]), which usually is cloud covered. The climate is wet, windy, and mild. About 66 inches (1,675 mm) of rain fall annually on the north coast at Edinburgh, the only permanent settlement. Plant and animal life includes elephant seals and other species not found elsewhere in the world.

Inaccessible is about 20 miles (32 km) west-southwest of Tristan da Cunha. Its cliffs are about 1,000 feet (300 m) high, and beneath them are occasional, narrow beaches. The small and flightless night rail is a bird peculiar to Inaccessible. Nightingale, the southernmost island, is 12 miles (19 km) southeast of Inaccessible and 20 miles south-southwest of Tristan da Cunha. Its coasts have low cliffs where millions of seabirds nest. The tiny islands of Middle and Stoltenhoff abut the north coast of Nightingale.

A Portuguese admiral, Tristão da Cunha, discovered the island group in 1506. Two unsuccessful attempts at settlement during the 17th century and one in 1810 preceded the stationing of a British garrison on Tristan da Cunha in 1816, when the island group was formally annexed by the United Kingdom. When the garrison was withdrawn in 1817, three of its members chose to stay, and over the years shipwrecked sailors, settlers of European extraction, and women from St. Helena, joined them. By 1886 there were 97 inhabitants. The settlement, named Edinburgh, was located on the largest lowland strip, about 0.5 mile wide and 5 miles long. In 1938 the six islands were made dependencies of St. Helena. During World War II, a naval meteorological and radio station was established on Tristan da Cunha; afterward a South African weather station was established.

A volcanic eruption on Oct. 9, 1961, directly threatened the settlement, and the inhabitants were evacuated to England via Nightingale Island. The main body of 198 islanders returned to the island in November 1963. A new harbour was built in 1965-67. Roads and a hospital, as well as electric, water, and sewerage facilities, were later constructed. Potatoes are the main crop and shore-based crawfish fishing the main industry; sales of the island's postage stamps also contribute to revenue.

Gough Island lies about 230 miles (370 km) south-southeast of Tristan da Cunha. It is about 8 miles long by 4 miles broad and is of volcanic origin. Pop. (1987) 296; (1990) 289.