Western Reef is a remote, wave‐swept rock platform located west of Point Somes, Chatham Island. The reef harbours a large resident New Zealand fur seal colony which, together with the low relief, exposed conditions, and frequency of storms, has left 80% of the reef free of vegetation.

The Chatham Island 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.