Semion Ivanovich Dezhnev (circa 1605 - 1673), Russian explorer who led the expedition that doubled known extent the easternmost promontory of the Eurasian continent in 1648 discovering that Asia is not connected to Alaska.

As his biographers concluded, Semion Dezhnev was born at the very beginning of the 17th century in Velikiy Ustiug in northern Russia. Like many of the enterprising Russian northmen of the time, he went to Siberia in search of his fortune, and served in Tobolsk and Yeniseisk. Dezhnev became well-known for his experience and bravery.

In 1647 he was approached by a fellow northman from Kholmogory F.A. Popov, who invited Dezhnev to join the Nizhekolymskaya (Low Kolyma) party and to sail by the sea from Kolyma towards the east in search of the precious "walrus zub (tooth) and fish bones" (walrus tusks and whale bones). The final destination of the voyage was supposed to be river Anadyr. But the ice conditions on the sea forced the party to abort their mission. That did not stop Dezhnev from trying it again the next year.

In 1648 Dezhnev, Popov, and Fedot Alekseev, another of the chief organizers of the expedition, led the party of about 90 to up to 105 men in seven small Arctic-worthy ships (koch) to river Anadyr. It took them ten weeks of sailing north to get to Anadyr estuary. The participation of Dezhnev in this leg of the voyage is undocumented. Only the activities of Fedot Alekseev can be traced today. From the estuary Dezhnev went up the river and founded Anadyrskiy ostrog (fort).

The same year Dezhnev sailed along the northern shores of the tip of Asia and discovered the Anian Strait between Asia and Alaska, thus proving that the Eurasian and the American continents are not connected. He followed the shoreline and doubled the Chukotka peninsula. In his reports Dezhnev gave the description of this legendary "Tabin-Promontorium", the existence of which was rumored by ancient geographers. Dezhnev also described two islands of chukchi people ("Ostrova zubatykh"), now known as Diomede Islands consisting of Ratmanov Island and Kruzenstern Island, lacated between Asia and Alaska in what is now Bering Strait. He collected interesting ethnographic data about chukchi people ("zubatiye") who decorated their lower lip with pieces of walrus tusks, stone or bone. The port of arrival of Dezhnev expedition is unknown.

In 1670 voevoda (governor) of Yakutsk kniaz (prince) Boryatinskiy entrusted Dezhnev with the mission to Moscow. Dezhnev was to deliver there the "sable treasury" and official documents. It took a year and five months for Dezhnev to successfully accomplish this journey. When he was over 60 years old, the old wounds received during his service at the borders of Russia and hard toil undermined his health. After severe illness Dezhnev died in Moscow in 1673.

The reports about the results of this expedition were buried in the departmental archives for a long time and only at the end of 19th century, following the petition of the Russian Geographic Society, the easternmost promontory of Eurasia was named after Dezhnev. Today we still have only scanty information about Dezhnev himself.

There is also a possibility that part of Dezhnev expedition could had discovered American mainland by reaching Alaska, and founded a settlement there. But this supposition is unconclusive because it could be some other Russian expedition.