The Chatham Islands form an archipelago in the Pacific Ocean about 680 kilometres (423 mi) southeast of mainland New Zealand. It consists of about ten islands within a 40-kilometre (25 mi) radius, the largest of which are Chatham Island and Pitt Island.
The archipelago is called Rekohu ("misty sun") in the indigenous language Moriori, and Wharekauri in Māori. It has officially been part of New Zealand since 1842 and includes the country's easternmost point, the Forty-Fours.
The islands are at about 43°53′S 176°31′W / 43.883°S 176.517°W / -43.883; -176.517, roughly 840 kilometres (520 mi) east of Christchurch, New Zealand. The nearest mainland New Zealand point to the Chatham Islands is Cape Turnagain, in the North Island at a distance of 650 kilometres (400 mi). The nearest mainland New Zealand city to the islands is Hastings, New Zealand, located 697 kilometres (430 mi) to the North-West. The islands cover a total of 966 square kilometres (373 sq mi), almost all of which is on the two main islands.
The Chatham Islands are a group of islands off the east coast of Oak Bay, British Columbia, Canada. All of the islands above the high tide mark (except the Alpha Islets ecological reserve) are in Chatham Islands Indian Reserve No. 4, under the control of the Songhees First Nation. Chatham Islands foreshore - defined as the land between low tide and the beginning of land based vegetation - is provincial Crown Land.
The Chatham Islands were named in 1846 by surveyors in honour of HMS Chatham, the escort ship of HMS Discovery, the ship of 18th-century British Explorer Captain George Vancouver on his voyage to chart the coastline of British Columbia between 1792 and 1794 (the Vancouver Expedition). The adjacent Discovery Island was named after the Discovery.