The International Date Line lies approximately 100 miles (87 nmi/160 km) to the west. Kure is the northern-most coral atoll in the world. It consists of a 6-mile (10 km) wide nearly circular barrier reef surrounding a shallow lagoon and several sand islets. There is a total land area of 213.097 acres (86.237 ha), with Green Island on the southeast side having 191.964 acres (77.685 ha) of this total. A small number of Hawaiian monk seals (Monachus schauinslandi) haul out on its beaches.