The Polish Corridor (Polnischer Korridor; Pomorze, Polski Korytarz), also known as the Danzig Corridor, Corridor to the Sea or Gdańsk Corridor, was a territory located in the region of Pomerelia (Pomeranian Voivodeship, eastern Pomerania, formerly part of West Prussia), which provided the Second Republic of Poland (1920–1939) with access to the Baltic Sea, thus dividing the bulk of Germany (Weimar Republic) from the province of East Prussia. At its narrowest point, the Polish territory was just 30 km wide. The Free City of Danzig (now the Polish cities of Gdańsk, Sopot and the surrounding areas), situated to the east of the corridor, was a semi-independent German speaking city-state forming part of neither Germany nor Poland, though united with the latter through an imposed union covering customs, mail, foreign policy, railways as well as defence.
A similar territory, also occasionally referred to as a corridor, was originally connected to the Polish Crown until 1308, and was later reclaimed as part of Royal Prussia during the period 1466–1772.
According to German historian Hartmut Boockmann the term "Corridor" was first used by Polish politicians, while Polish historian Grzegorz Lukomski writes that the word was coined by German nationalist propaganda of the 1920s. Internationally the term was used in the English language already as early as March 1919 and whatever its origins, it became a widespread term in English language usage.
The equivalent German term is Polnischer Korridor. Polish names include korytarz polski ("Polish corridor") and korytarz gdański ("Gdańsk corridor"); however, reference to the region as a corridor came to be regarded as offensive by interwar Polish diplomats. Among the harshest critics of the term corridor was Polish Foreign Minister Józef Beck, who in his May 5, 1939 speech in Sejm (Polish parliament) said: "I am insisting that the term Pomeranian Voivodeship should be used. The word corridor is an artificial idea, as this land has been Polish for centuries, with a small percentage of German settlers".