Atafu, formerly known as the Duke of York Group, is a group of 52 coral islets within Tokelau in the south Pacific Ocean, 500 kilometres north of Samoa. Covering 2.5 square kilometres, 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 (5.8 sq mi). The atoll lies some 800 kilometres south of the equator at 8° 35' South, 172° 30' West.