Much of the area between the bays is taken up by the large Te Whanga Lagoon, which drains to the sea to the east, into the southern half of Hanson Bay. This lagoon covers about , and drains several small rivers that rise in the hills at the south end of the island. The next largest lakes are Rangitahi and Huro, respectively northeast and southwest of Te Whanga. The central and north part of Chatham Island are mostly flat, with altitudes ranging from a few metres on the northeast and centre to 50 m on the northwest, but with a few scattered hillocks. The south part is higher, generally sloping down towards north and west; about half of it is over 150 m above sea level. The south coast of the island is mostly cliffs 100 m high or more. The highest point of the island (299 m) lies close to its southernmost point.