Saint Helena, Ascension, and Tristan da Cunha Geography Profile

islands in the South Atlantic Ocean, about midway between South America and Africa; Ascension Island lies 1,300 km (800 mi) northwest of Saint Helena; Tristan da Cunha lies 4,300 km (2,700 mi) southwest of Saint Helena

Saint Helena: 15 57 S, 5 42 W;

Ascension Island: 7 57 S, 14 22 W;

Tristan da Cunha island group: 37 15 S, 12 30 W

Africa

slightly more than twice the size of Washington, DC

Saint Helena: tropical marine; mild, tempered by trade winds;

Ascension Island: tropical marine; mild, semi-arid;

Tristan da Cunha: temperate marine; mild, tempered by trade winds (tends to be cooler than Saint Helena)

the islands of this group are of volcanic origin associated with the Atlantic Mid-Ocean Ridge

Saint Helena: rugged, volcanic; small scattered plateaus and plains;

Ascension: surface covered by lava flows and cinder cones of 44 dormant volcanoes; terrain rises to the east;

Tristan da Cunha: sheer cliffs line the coastline of the nearly circular island; the flanks of the central volcanic peak are deeply dissected; narrow coastal plain lies between The Peak and the coastal cliffs

lowest point: Atlantic Ocean 0 m

highest point: Queen Mary's Peak on Tristan da Cunha 859 m; Green Mountain on Ascension Island 818 m; Mount Actaeon on Saint Helena Island 2,060 m

fish, lobster

Saint Helena - population is concentrated in and around the capital Jamestown in the northwest, with another significant cluster in the interior Longwood area; Ascension - largest settlement, and location of most of the population, is Georgetown; Tristan da Cunha - most of the nearly 300 inhabitants live in the northern coastal town of Edinburgh of the Seven Seas

active volcanism on Tristan da Cunha

volcanism: the island volcanoes of Tristan da Cunha (2,060 m) and Nightingale Island (365 m) experience volcanic activity; Tristan da Cunha erupted in 1962 and Nightingale in 2004

development threatens unique biota on Saint Helena

Saint Helena harbors at least 40 species of plants unknown elsewhere in the world; Ascension is a breeding ground for sea turtles and sooty terns; Queen Mary's Peak on Tristan da Cunha is the highest island mountain in the South Atlantic and a prominent landmark on the sea lanes around southern Africa