The Chatham Islands consist of two main islands (Chatham and Pitt), around which are several fascinating smaller islands, islets, rock stacks and reefs. Of these, the two largest are Mangere and Rangatira.

These two Crown-owned islands are designated Nature Reserves and are vital for the conservation of the Chatham Islands flora, fauna and ecosystems. Free of all introduced predators and pests, these are some are the last remaining refuges of Chatham endemic species. To ensure that the predator-free status of these islands is maintained, access to both Mangere and Rangatira is tightly-controlled. Access is by permit only and is generally restricted to those undertaking management activities.