Antarctica is Earth's southernmost continent, overlying the South Pole. Situated in the southern hemisphere and largely south of the Antarctic Circle, Antarctica is surrounded by the Southern Ocean. At 14.4 million square kilometers (5.4 million sq mi), it is the fifth-largest continent in area after Asia, Africa, North America, and South America; in turn, Europe and Australia are smaller. Some 98% of Antarctica is covered by ice, which averages at least 1.6 kilometers (1.0 mi) in thickness.