The Romanian Bridgehead (Polish: Przedmoście rumuńskie; Romanian: Capul de pod român) was an area in southeastern Second Polish Republic that is now located in Ukraine. During the invasion of Poland in 1939 at the start of the Second World War, the Polish commander-in-chief, Marshal of Poland Edward Rydz-Śmigły, ordered all Polish troops fighting east of the Vistula (approximately 20 divisions still retaining the ability to co-operate) to withdraw towards Lwów and then to the hills along the borders with the Kingdom of Romania and the Soviet Union on 14 September. After the Soviets attacked on 17 September, Rydz-Śmigły ordered all units to withdraw to Romania and the Kingdom of Hungary, but communications had become disrupted although smaller units crossed outside the major battles.
The plan was a default plan in case it was impossible to defend the Polish borders, and it assumed that the Polish forces would be able to retreat to the area, organise a successful defence until the winter and hold out until the promised French offensive on the Western Front had started. Rydz-Śmigły predicted that the hills, valleys, swamps and the rivers Stryj and Dniester would provide natural lines of defence against the Nazi German advance. The area was also home to many ammunition dumps that were prepared for the third wave of Polish troops, and it was linked by transport to the Romanian port of Constanța, which could be used to resupply the Polish troops.
View the full Wikipedia page for Romanian Bridgehead
