Caroline Island lies near the southeastern end of the Line Islands, a string of atolls extending across the equator, south of the Hawaiian Islands in the central Pacific Ocean. The slightly crescent-shaped atoll has a land area of . It consists of approximately 39 separate islets, surrounding a narrow lagoon; the smallest islet, Motu Atibu, may have disappeared. The islets—which rise to a height of above sea level—share a common geologic origin, and consist of sand deposits and limestone rock set atop a coral reef. According to the path of the International Date Line, the atoll is the easternmost point of land on Earth.