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.