Lwów Voivodeship ( ) was an administrative unit of interwar Poland ( 1918 – 1939 ) . Because of the Nazi-Soviet invasion of Poland in accordance with the secret Molotov – Ribbentrop Pact , it became occupied by both the Wehrmacht and the Red Army in September 1939 . Following the conquest of Poland however , the Polish underground administration existed there until August 1944 . The Voivodeship was not returned to Poland after the war ended . It was split diagonally just east of Przemyśl ; with its eastern half ceded to the Ukrainian SSR at the insistence of Joseph Stalin during the Tehran Conference confirmed ( as not negotiable ) at the Yalta Conference of 1945
Yalta Conference
Yalta Conference
Lwów Voivodeship