Penrhyn (also called Tongareva, Māngarongaro, Hararanga, and Te Pitaka) is an atoll in the northern group of the Cook Islands in the south Pacific Ocean. The northernmost island in the group, it is located at north-north-east of the capital island of Rarotonga, 9 degrees south of the equator. Its nearest neighbours are Rakahanga and Manihiki, approximately to the southwest. Once one of the most heavily populated atolls, it was almost completely depopulated by Peruvian slavers in 1864. Penrhyn is a roughly circular coral atoll with a circumference of approximately , enclosing a lagoon with an area of . The atoll is atop the highest submarine volcano in the Cook Islands, rising from the ocean floor. The atoll is low-lying, with a maximum elevation of less than . The total land area is . The atoll rim consists of 18 major islets. Clockwise, from the Northwest, these are: Tokerau Painko Ruahara Takuua Veseru Tuirai Pokerekere Islet Kavea Temata Patanga Tepuka Ahu a Miria Atutahi Moturakina Atiati Mangarongaro Moananui Islet Matunga Tekasi Polynesians are believed to have lived on Penrhyn since 900 or 1000 AD. According to oral tradition, the island was fished up by Vatea, using part of his thigh as bait, and has been inhabited since the time of creation. Other legends tell of the island being visited by various ancestors of Tangiia-nui of Rarotonga on their way from Samoa to Tahiti. Other ancestors came from Aitutaki and Rakahanga. The Polynesians named the atoll Tongareva ("Tonga floating in space", "Tonga-in-the-skies" and "Away from the South"). The island was first discovered by Europeans in 1788, when the Lady Penrhyn commanded by Captain William Crofton Sever, passed by the island on 8 August while returning from delivering the first convicts to Australia. It was later visited by the Russian explorer Otto von Kotzebue in April 1816, and then by the American brig USS Porpoise, under command of Lieutenant Commander Cadwalader Ringgold as part of the United States Exploring Expedition in February 1841.