(1856–1920), American explorer, born in Cresson, Pa., and educated at Bowdoin College. In 1881 he became a civil engineer in the U.S. Navy; in this capacity he participated in the Nicaragua Canal Survey in 1884–85 and made an exploration into Greenland in 1886. He led further expeditions to Greenland in 1891–92 and from 1893 to 1895. He proved Greenland was an island rather than a continent and that the Greenland ice cap extended no farther north than lat 82° N; he also contributed to scientific knowledge of Inuit (Eskimo) ethnology and of glacial formation. Between 1898 and 1902 Peary engaged in surveys in Greenland. In 1902 and in 1905–6 he made unsuccessful attempts to reach the North Pole, coming within 280 km (174 mi) of his goal on the latter trip.

On July 17, 1908, Peary led another expedition to the Pole, and on April 7, 1909, he and a small party consisting of his assistant Matthew A. Henson (1867–1955) and four Inuit reached their target. On Sept. 6, 1909, the day he announced his achievement, Peary learned that the discovery of the Pole had been claimed five days previously by the American explorer and surgeon Frederick Albert Cook. Examination by experts established that the doctor’s claim was false; Peary’s records were accepted as genuine. In 1911, the year Peary retired, Congress recognized his discovery as unimpeachable, and he was given the rank of rear admiral before his retirement. His books include The North Pole (1910) and Secrets of Polar Travel (1917).