Wuvulu is a low coral island of volcanic origin with a maximum elevation of 3 m (10 feet) above sea level. It is approximately 19.3 km (12 miles) in circumference and 4 km (2½ miles) by 7.2 km (4½ miles) in diameter with a surface area of 1,400 ha (3,600 acres). The island is completely encircled by a fringing coral reef with no natural harbor, making it impossible to anchor ships. Wuvulu is the westernmost island of the Western Islands of the Bismarck Archipelago, located 224.5 nautical miles (416 km) to the west of Manus Island and the Admiralty Islands, 140.3 nautical miles (260 km) north of Wewak, East Sepik Province, Papua New Guinea, and more than 593 nautical miles (1,100 km) south of the Carolines Archipelago.