Battle of the Niemen River

The Battle of the Niemen River was the second-greatest battle of the Polish–Soviet War. It took place near the middle Neman River between the cities of Suwałki, Grodno and Białystok. After suffering almost complete defeat in the Battle of Warsaw (August 1920), Mikhail Tukhachevsky's Red Army forces tried to establish a defensive line, against Józef Piłsudski's counter-attacking Polish Army, running northward from the Polish-Lithuanian border to Polesie, and centering on Grodno. Between September 15 and September 25, 1920, the Poles outflanked the Soviets, once again defeating them. After the mid-October Battle of the Szczara River, the Polish Army had reached the Tarnopol-Dubno-Minsk-Drissa line.

Although this part of the conflict is usually referred to as a battle both in Polish and Russian historiography, some historians argue that it was more of a military operation with a series of battles fought often several hundred kilometres apart.