The Neva (ˈniːvə , UKalsoˈneɪvə ; ) is a river in northwestern Russia flowing from Lake Ladoga through the western part of Leningrad Oblast (historical region of Ingria) to the Neva Bay of the Gulf of Finland. Despite its modest length of , it is the fourth-largest river in Europe in terms of average discharge (after the Volga, the Danube and the Rhine).
The Neva is the only river flowing from Lake Ladoga. It flows through the city of Saint Petersburg, the three smaller towns of Shlisselburg, Kirovsk and Otradnoye, and dozens of settlements. It is navigable throughout and is part of the Volga–Baltic Waterway and White Sea–Baltic Canal. It is the site of many major historical events, including the Battle of the Neva in 1240 which gave Alexander Nevsky his name, the founding of Saint Petersburg in 1703, and the Siege of Leningrad by the German army during World War II. The river played a vital role in trade between Byzantium and Scandinavia.
The earliest people in recorded history known to have inhabited the area are the Finnic people. Neva is widespread in Finnic languages, having quite cognate meanings. In Finnish it means poor fen, in Karelian: watercourse and in Estonian (as nõva): waterway.
It has been postulated the name could derive from Indo-European adjective newā which means new – the river began its flow some time between 2000 BC and 1250 BC. However, the local place names with such influence coincide with Scandinavian traders and Slavs' first main settlement in the region, in the 8th century CE.
In the Paleozoic, 300–400 million years ago, all the delta region was covered by a sea. Modern relief, eminences, were formed by glacial scouring. Its retreat formed the Littorina Sea, the level of which was higher than its successor the Baltic Sea. Then, the Tosna was flowing in the modern lower half of the Neva as today, into the Litorinal Sea. In the north of the Karelian Isthmus, the sea was united by a wide strait with Lake Ladoga. The Mga then flowed to the east, into Lake Ladoga, near the modern source of the Neva.