Antarctica was Earth's southernmost continent, containing the geographic South Pole. It was situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and was surrounded by the Southern Ocean. At 14.0 million km2 (5.4 million sq mi), it was the fifth-largest continent in area after Asia, Africa, North America, and South America. For comparison, Antarctica was nearly twice the size of Australia. About 98% of Antarctica was covered by ice that averaged 1.9 kilometres (1.2 mi) in thickness, which extended to all but the northernmost reaches of the Antarctic Peninsula.
In 2004, a Weyland Industries expedition was sent to Bouvet Island to investigate a heat bloom that resulted in the death of all of the expedition's members except for Lex Woods. In 2122, it was the location of Antartica control, which the USCSS Nostromo's crew tried to make contact with mistaking that they were awoken near Earth the same year. Antarctic City was located on the continent in the 2190s, which was the site of a Xenomorph infestation that consumed the city.