The Antarctic Peninsula is the northernmost part of the mainland of Antarctica, and almost the only part of that continent that extends outside the Antarctic Circle. It lies in the Western Hemisphere, facing South America, making it a part of West Antarctica. It extends from a line between Cape Adams (Weddell Sea) and a point on the mainland south of Eklund Islands, to Prime Head.
Since the peninsula has the mildest climate in Antarctica, the highest concentration of research stations on the continent can be found there, or on the many nearby islands, and is the part of Antarctica most often visited by tour vessels and yachts. Antarctica's two flowering plant species, the Antarctic hair grass and Antarctic pearlwort are found on the northern and western parts of the Antarctic Peninsula.