French Southern and Antarctic Lands, overseas territory of France, including Adélie Land, which covers c.200,000 sq mi (520,000 sq km) in Antarctica, and a number of islands in the S Indian Ocean. The largest of these is Kerguelen (1,318 sq mi/3,414 sq km). One of 300 islands in the Kerguelen Archipelago, it is a base for research, seal hunting, and whaling. The Crozet Islands, to the west, and Saint Paul and Amsterdam islands, to the northeast, are also part of the territory.

Antarctic Peninsula, glaciated mountain region of W Antarctica, extending c.1,200 mi (1,930 km) N toward South America; in the south, volcanic peaks rise to c.11,000 ft (3,350 m). Most of its NE coast is fringed by the Larsen ice shelf. The peninsula is surrounded by numerous islands, including the South Shetlands and the Palmer Archipelago. The tip of the peninsula, 670 mi (1,078 km) from Cape Horn, is Antarctica's farthest point from the South Pole. The continent's only flowering plants are found on the peninsula.

The northwest coast of the peninsula is believed to have been mapped by the British navigator James Bransfield in Jan., 1820, and was explored by sealers in 1820-21. First considered to be part of the continent, the peninsula was later (1928) thought to be a group of islands; the John Rymill expedition (1934-37) proved its peninsularity. It was originally named Palmer Peninsula by Americans for Nathaniel Palmer, a U.S. captain who explored the area in Nov., 1820. In 1832, Britain claimed it and called it Graham Land and Trinity Peninsula. Argentina claimed it in 1940 as San Martin Land and Chile in 1942 as O'Higgins Land. In 1964, by international agreement, the entire feature was called the Antarctic Peninsula; Graham Land, Trinity Peninsula, and Palmer Land are used as local names. The peninsula is now the site of numerous research stations. The disintegration of a Rhode Island-sized section of the Larsen ice shelf over a few weeks time in 2002, although directly due to locally warmer temperatures, was also regarded by some scientists as a result of the more general global warming.

Antarctic Ocean: see Southern Ocean.

Antarctic Circle, imaginary circle on the surface of the earth at 661/2°S lat., i.e., 231/2° north of the South Pole. It marks the southernmost point at which the sun can be seen at the winter solstice (about June 22) and the northernmost point of the southern polar regions at which the midnight sun is visible.

Parallel of latitude approximately 66°30' south of the Equator that circumscribes the southern frigid zone. It marks the northern limit of the area within which, for one day or more each year, the sun does not set or rise. The length of continuous day or night increases southward from the Antarctic Circle, mounting to six months at the South Pole.

Learn more about Antarctic Circle with a free trial on Britannica.com.