The Hel Fortified Area (Polish: Rejon Umocniony Hel) was a set of Polish fortifications, constructed on the Hel Peninsula in northern Poland, in close proximity to the interwar border of Poland and the Third Reich. It was created in 1936, upon a decree of President Ignacy Moscicki. It covered most part of the peninsula, and during Polish September Campaign, it was the last place of Poland to surrender to the invading Wehrmacht (for more information, see Battle of Hel). During World War II, the naval base in Hel was used as a major training facility for U-boat crews.
After Poland regained independence in the fall of 1918 (see: Partitions of Poland), and the symbolic wedding ceremony with the Baltic Sea by units of the Polish Army under General Józef Haller de Hallenburg (Puck, February 10, 1920), Polish military authorities began preparations of a fortified army garrison along the coast. As early as July 22, 1920 General Kazimierz Sosnkowski ordered construction of a strategic rail line which ran from Puck, through Wladyslawowo, to Hel. The line was completed in 1921, together with telegraph connection, by the logistics units of the Polish Army. A road was constructed along the line.