Chatham Island is by far the largest island of the Chatham Islands group, in the south Pacific Ocean off the eastern coast of New Zealand's South Island. It is said to be "halfway between the equator and the pole, and right on the International Date Line", though the point (180°, 45°S) in fact lies ca. 173 miles WSW of the island's westernmost point. The island is called Rekohu ("misty skies") in Moriori, and Wharekauri in Māori
The island was named after the survey shipHMS Chatham which was the first European ship to locate the island in 1791. It covers an area of 920 square kilometres Chatham Island lies 650 km south-east of Cape Turnagain, the nearest point of mainland New Zealand to the island.