The Northern Sea Route (Russian: Се́верный морско́й путь, Severnyy morskoy put’, shortened to Sevmorput' ) is a shipping lane officially defined by Russian legislation from the Atlantic Ocean to the Pacific Ocean specifically running along the Russian Arctic coast from Murmansk on the Barents Sea, along Siberia, to the Bering Strait and Far East. The entire route lies in Arctic waters and parts are free of ice for only two months per year. Before the beginning of the 20th century it was called the Northeast Passage, and is still sometimes referred to by that name.

The motivation to navigate the North East Passage was initially economic. In Russia the idea of a possible seaway connecting the Atlantic and the Pacific was first put forward by the diplomat Gerasimov in 1525. However, Russian settlers and traders on the coast of the White Sea, the Pomors, had been exploring parts of the route as early as the 11th century.

During a voyage across the Barents Sea in search of the North East Passage in 1553, English explorer Hugh Willoughby thought he saw islands to the north, and islands called Willoughby's Land were shown on maps published by Plancius and Mercator in the 1590s and they continued to appear on maps by Jan Janssonius and Willem Blaeu into the 1640s.