The Neman, Niemen, Nioman, Nemunas or Memel is a river in Europe that rises in central Belarus and flows through Lithuania then forms the northern border of Kaliningrad Oblast, Russia's western exclave, which specifically follows its southern channel. It drains into the Curonian Lagoon, narrowly connected to the Baltic Sea. It flows about , so is considered a major Eastern European river. It flows generally west to Grodno within of the Polish border, north to Kaunas, then westward again to the sea.
The largest river in Lithuania, and the third-largest in Belarus, it is navigable for most of its length. It starts from two small headwaters merging about southwest of the town of Uzda – about southwest of capital city Minsk. Only , an eastward meander, contributes to the Belarus–Lithuania border. Thereafter the river includes notable loops along a minor tectonic fault.
Its drainage basin settled in the late Quaternary to be roughly along the edge of the last glacial sheet so dates to about 25,000 to 22,000 years BC. Its depth varies from in its upper courses to in the lower basin.
Numbers
The total length of the Nioman/Nemunas/Neman is . It is the 4th longest river in the Baltic Sea basin. Over its entire length, flows in Belarus and in Lithuania. A stretch is the border between Lithuania and Russia's Kaliningrad oblast. Its greatest depth is , and at its widest it extends about . The Nioman/Nemunas/Neman is a slow river; it flows at about . During floods, water discharge can increase up to 11-fold, to more than . Severe floods occur on the lower reaches of the river about every 12 – 15 years, which sometimes wash out bridges.
The Nioman/Nemunas/Neman is an old river, dating back to the last glacial period. Its valley is now up to deep and broad. It has about 105 first-class tributaries, the largest being the rivers Neris (Viliya) (), Shchara (), and Šešupė (). Fifteen of the tributaries are longer than . In the complete Nioman/Nemunas/Neman basin, there are tributaries extending to the 11th order. The Nemunas basin in Lithuania drains more than 20,000 rivers and rivulets and covers 72% of Lithuania's territory. The total area of the Nioman/Nemunas/Neman basin is , of which are within Belarus, the Lithuanian portion of this basin is 46,. Valley of Neman in Grodno Region is the lowest point above sea level in Belarus at .
River course
Nemunas loops
Due to their location, "The Nemunas loops" are often described using the Lithuanian name for the river. In 1992 Nemunas Loops Regional Park was founded. Its goal is to preserve the loops (Lithuanian: vingis) that the river makes in the Punia forest. Near Prienai, the Nemunas makes a loop (like a teardrop) coming within of completing the loop. The Nemunas flows along the double bend between Balbieriškis and Birštonas for and then moves in a northerly direction for only . The loops are not conventional river meanders; they follow underlying tectonic structures. The faults are the source of local mineral springs. The area is historically and culturally significant. Its castles served as the first line of defense against forays by the Teutonic knights.
Delta
At its delta the Nemunas splits into a maze of river branches and canals mixing with polders and wetlands and is a very attractive destination for eco-tourism. The four main distributaries are Atmata, Pakalnė, Skirvytė (the southern mouth, marking the international border) and Gilija. The river plays a crucial part in the ecosystem of the Curonian Lagoon. It provides the main water inflow to the lagoon and keeps the water almost fresh. This allows fresh water and brackish water animals to survive there. As the delta extends north the lagoon opposite narrows. Since the delta is in Lithuania, it is often referred to as Nemunas Delta. Nemunas Delta Regional Park was created in the delta in 1992.
Tributaries
The following rivers are tributaries to the river Neman/Nemunas (from source to mouth):
Left: Servach, Mowchadz’, Shchara, Zelvyanka, Svislach, Lasosna, Czarna Hańcza, Zembrė, Peršėkė, Šešupė, Tylzha Right: Western Berezina, Gauja, Kotra, Haradnichanka, Merkys, Verknė, Strėva, Neris, Nevėžis, Dubysa, Mituva, Jūra, Minija
Largest settlements on the river
From west to east, the largest settlements are Sovetsk/Tilsit, Neman, Kaunas, Alytus, Druskininkai, Grodno, and Masty.
Significance in culture
Ptolemy referred to Neman as Chronos (although competing theories suppose Chronos was in fact Pregolya).
The river has lent its name to the Neman Culture, a Neolithic archaeological subculture.