Germany–Poland border

Moving Poland west

In February 1945, at Yalta, the three Allied leaders agreed that Poland's eastern frontier should follow the Curzon Line, giving land to the Soviet Union. In return they recognised that Poland “must receive substantial accessions in territory in the north and west”. The final western frontier was left for a peace conference.^[4]

At Potsdam that summer, the Big Three placed the German lands east of a line along the Oder and the western Neisse under Polish administration. The line started on the Baltic “immediately west of Swinamunde” (Świnoujście) and ran south to the Czechoslovak frontier.^[1] The protocol, dated 1 August 1945, still called this temporary: the final frontier was to “await the peace settlement”.^[1]

Some of the new lines cut through towns. Stettin, which had grown into Germany's premier Baltic port, lay mainly on the west bank of the Oder but was assigned to Poland and became Szczecin.^[5] Guben and Gubin used to be a single town until the new border along the Neisse split them.^[6]

People moved too

Poland began deporting the German residents of the territories it received.^[7] At Potsdam the Allies accepted that German populations remaining in Poland, Czechoslovakia and Hungary would be transferred to Germany. They asked only that transfers be “effected in an orderly and humane manner”, and that further expulsions be suspended for the time being.^[1]

Poland had lost land in the east at the same time, and the State Department's historians describe the German territory as given “in exchange” for it.^[7] Decades later, the 1990 treaty still recalled “the loss of their homes sustained by many Germans and Poles as a result of displacement or evacuation”.^[2]

Two Germanys, two answers

East Germany accepted the line first. In June 1950 its government and Poland's declared the Oder–Neisse line their mutual boundary, and on 6 July Prime Ministers Otto Grotewohl and Józef Cyrankiewicz signed an eight-article agreement at Zgorzelec.^[8] An act recording the completed demarcation was signed in Frankfurt (Oder) on 27 January 1951.^[3]

The United States refused to accept it. In a statement the State Department fully supported, John McCloy said the frontier could only be settled in a peace treaty with Germany, not “unilaterally or bilaterally”, and that the US had not recognised the Oder–Neisse boundary.^[8]

West Germany recognised the line in the Treaty of Warsaw, signed by Chancellor Willy Brandt and Prime Minister Cyrankiewicz on 7 December 1970. It acknowledged the Oder–Neisse line as Poland's western border and guaranteed that border's inviolability. The West German parliament ratified it in 1972.^[9] Brandt told West Germans on television that the loss of the east followed from “the million-fold crimes of the Hitler regime”.^[10]

Final in 1990

German reunification needed a final answer. The Two-Plus-Four Treaty, signed in Moscow on 12 September 1990 by the two German states and the four wartime Allies, made united Germany's borders definitive. It also required Germany and Poland to confirm their border in a treaty binding under international law.^[11]

Foreign ministers Hans-Dietrich Genscher and Krzysztof Skubiszewski signed that treaty in Warsaw on 14 November 1990. It confirmed the line set by the 1950 agreement, the 1951 demarcation document, the 1989 Oder Bay treaty and the 1970 Warsaw treaty. Both sides declared they had no territorial claims on each other and would advance none in the future.^[2] It came into force on 16 January 1992.^[2]

At sea, the border follows the 1989 treaty between East Germany and Poland. Its line runs roughly north from the coast, and it keeps the whole northern approach to the ports of Szczecin and Świnoujście inside Polish waters or the high seas.^[3]

“The Contracting Parties declare that the existing frontier between them shall be inviolable now and in the future, and pledge absolute respect for each other's sovereignty and territorial integrity.”^[2]

Open, then checked again

Checks on the border disappeared after Poland joined the Schengen open-borders zone in December 2007.^[6] Germany brought back controls on 16 October 2023.^[12] By May 2025, Chancellor Friedrich Merz's new government had added fresh checks to push back anyone trying to enter without the necessary documents, including most asylum seekers. On the Neisse bridge between Guben and Gubin, police were stopping and inspecting vehicles.^[6]

Poland answered with its own temporary controls on the German and Lithuanian borders from 7 July 2025. Prime Minister Donald Tusk said Germany had been refusing entry to migrants at the Polish–German border.^[12]