Te Whanga Lagoon dominates the geography of Chatham Island, covering a significant area of 69 square miles. It is the outflow of several small rivers from the island's hilly south, draining to the Pacific via gaps in Hanson Bay on the east coast of the island. It contains many fossilized shark teeth that can be collected from the edges of the lagoon.

The Chatham Islands sit on the Chatham Rise, a large, relatively shallowly submerged (no more than 1,000 metres deep)#160;reach of the Zealandia continent. The Chatham Islands are 800 kilometres east of New Zealand's South Island in the Pacific Ocean. The islands are generally hilly with the coasts a varied mixture including cliffs and sand dunes, beaches and lagoons. Chatham and Pitt are the only inhabited islands, with the remaining smaller islands being conservation reserves with access restricted or prohibited. The livelihoods of the inhabitants depend mainly on agriculture, fishing and tourism.