The Polish Corridor refers to the roughly 140-kilometre-wide band of former West Prussian territory awarded to the reconstituted Republic of Poland by the Treaty of Versailles (signed 28 June 1919, in force 10 January 1920). Its purpose was to honour the thirteenth of US President Woodrow Wilson's Fourteen Points, which called for an independent Poland with "free and secure access to the sea." The corridor ran along the lower Vistula to the Baltic coast near Gdynia, and it physically separated the German exclave of East Prussia from the main body of the Weimar Republic.
The neighbouring port city of Danzig (Gdańsk), with a predominantly German-speaking population, was not included in the corridor itself. Instead, it was constituted as the Free City of Danzig under League of Nations protection, with Poland holding specific rights over its foreign relations, customs union, and use of the harbour. Poland subsequently developed the nearby village of Gdynia into a major Baltic port during the 1920s and 1930s to reduce dependence on Danzig.
The corridor was a persistent source of German revanchist grievance throughout the interwar period. Successive Weimar and later Nazi governments demanded its revision, citing the disruption of transit between Berlin and Königsberg and the presence of ethnic German minorities. In October 1938 and again in March 1939, Nazi Germany formally demanded the annexation of Danzig and an extraterritorial road and rail link across the corridor. Poland's refusal, backed by Anglo-French security guarantees issued on 31 March 1939, formed the immediate diplomatic backdrop to the German invasion of Poland on 1 September 1939, which triggered the Second World War.
After 1945, the Potsdam Conference placed the former corridor and most of East Prussia under Polish or Soviet administration, and the postwar expulsion of the German population resolved the territorial dispute in Poland's favour. The Oder–Neisse line was definitively recognised by reunified Germany in the 1990 German–Polish Border Treaty.
Example
In March 1939, German Foreign Minister Joachim von Ribbentrop demanded that Poland cede Danzig and permit an extraterritorial highway across the Polish Corridor, a demand Warsaw rejected with British and French backing.
Frequently asked questions
To fulfil the Fourteen Points pledge of giving Poland access to the Baltic Sea, the Treaty of Versailles assigned former West Prussian territory with a substantial Polish-speaking population to Poland.
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