Atafu, formerly known as the Duke of York Group, is a group of 42 coral islets within Tokelau in the south Pacific Ocean, 500 km north of Samoa. Covering 2.5 km², it is the smallest of the three islands that constitute Tokelau, and is composed of an atoll surrounding a central lagoon, which itself covers some 15 km². The atoll lies some 800 kilometres south of the equator at 8° 35' South, 172° 30' West.