The Oder–Neisse line (Polish: granica na Odrze i Nysie Łużyckiej, German: Oder-Neiße-Grenze) is the border between Germany and Poland which was drawn in the aftermath of World War II. The line is formed primarily by the Oder and Lusatian Neisse rivers, and meets the Baltic Sea west of the seaport cities of Szczecin (German: Stettin) and Świnoujście (Swinemünde). All pre-war German territory east of the line and within the 1937 German boundaries (23.8% of the former Weimar Republic) were discussed at the Potsdam Conference, and were placed under International Law Administrative status of Poland (for most of the area) and the Soviet Union (northern East Prussia) after the war (pending the final World War II peace treaty for Germany), and the vast majority of its native German population was killed, fled or expelled by force. The Oder–Neisse line marked the border between the German Democratic Republic (East Germany) and Poland from 1950 to 1990. East Germany confirmed the border with Poland in 1950, while West Germany, after a period of refusal, finally accepted the border (with reservations) in 1970. In 1990 the newly reunified Germany and the Republic of Poland signed a treaty recognizing it as their border.
The Lusatian Neisse (Czech: Lužická Nisa; German: Lausitzer Neiße; Polish: Nysa Łużycka; Upper Sorbian: Łužiska Nysa; Lower Sorbian: Łužyska Nysa) is a 252-kilometre (157 mi) long river in Central Europe. It rises in the Jizera Mountains near Nová Ves nad Nisou, Czech Republic, reaching the tripoint with Poland and Germany at Zittau after 54 kilometres (34 mi), and later forming the Polish-German border for a length of 198 kilometres (123 mi). The Lusatian Neisse is a left-bank tributary of the river Oder, into which it flows between Neißemünde-Ratzdorf and Kosarzyn north of the towns of Guben and Gubin.
According to the 1945 Potsdam Agreement in the aftermath of World War II, the river became part of the Polish western border with Germany (the Oder-Neisse line). Being the longest and most notable of the three rivers named Neisse (Neiße) (German) or Nysa (Polish) (the two other rivers being Nysa Kłodzka (Glatzer Neisse) and Nysa Szalona (Wütende Neiße or Jauersche Neiße)), it is simply referred to as the Nysa or Neisse. An older Polish variant, no longer used, was Nissa.
The Lusatian Neisse is a river in Central Europe.
Neisse or German: Neiße may also refer to:
Nysa [ˈnɨsa] (German: Neisse or Neiße) is a town in southwestern Poland on the Nysa Kłodzka river with 47,545 inhabitants (2006 official estimate), situated in the Opole Voivodeship. It is the capital of Nysa County. It comprises the urban portion of the surrounding Gmina Nysa, a mixed urban-rural commune with a total population of 60,123 inhabitants. It is the largest city in Poland that is not located in a strictly "urban" commune.
Nysa is one of the oldest towns in Silesia. It was probably founded in the 10th century and afterwards became the capital of a principality of its name, which around 1200 became part of the Bishopric of Wrocław as the Duchy of Nysa. The town's fortifications from 1350 served to defend against the Hussites in 1424. The town and the duchy was part of Lands of the Bohemian Crown in years 1342 - 1742.
During the Thirty Years' War (1618–1648) it was besieged three times. The first Silesian War (1740–41, War of the Austrian Succession) ended Austrian sovereignty over Silesia and left the town in the hands of King Frederick II of Prussia, who laid the foundations of its modern fortifications. On 25 August 1769 Neisse was the site of a meeting between Frederick II and Emperor Joseph II, co-regent in the Habsburg Monarchy of Austria.