Manus Island is part of Manus Province in northern Papua New Guinea and is the largest of the Admiralty Islands. It is the fifth-largest island in Papua New Guinea, with an area of 2,100 km2 (810 sq mi), measuring around 100 km × 30 km (60 mi × 20 mi). Manus Island is covered in rugged jungles which can be broadly described as lowland tropical rain forest. The highest point on Manus Island is Mt. Dremsel, 718 metres (2,356 ft) above sea level at the centre of the south coast. Manus Island is volcanic in origin and probably broke through the ocean's surface in the late Miocene, 8 to 10 million years ago. The substrate of the island is either directly volcanic or from uplifted coral limestone.