Territorial changes of Polish Voivodeships on 1 April 1938

On 1 April 1938, borders of several western and central Voivodeships of the Second Polish Republic changed considerably. This included such Voivodeships as Pomerania, Poznan, Warsaw, Lodz, Bialystok, Lublin and Kielce.

Source: Wikipedia — Territorial changes of Polish Voivodeships on 1 April 1938 (CC BY-SA 4.0)