Polish–Soviet border agreement of August 1945

The treaty also recognised the division of the former German East Prussia and ultimately approved the finalised delimitation line between the Soviet Union and Poland: from the Baltic Sea, to the border tripoint with Czechoslovakia in the Carpathians.

However, after the liberation of Western Ukraine and Belarus in summer of 1944, a Polish committee formed in the town of Sapotskin sent a letter to Moscow asking that they remain part of Poland.

In October 1944 these were joined by a further transfer of Lubaczów, Horyniec, Laszki, Uhnów and Sieniawa raions of the Lviv Oblast from the Ukrainian Soviet Socialist Republic.

Soon afterwards World War II finished, and as the Provisional Government continued to transfer administration from military to civil bodies, it also finalised its new borders with its neighbors, and in particular, the Soviet Union.

Soviet claims, which became the main problem preventing cooperation between the Polish government in London and Moscow during the war, were then accepted by PKWN activists in July 1944.

Their consent to the Curzon line signed on 27 July 1944 (Relinquishing half of the Białowieża Forest was Stalin's only concession, and representatives of the Polish Committee of National Liberation were afraid to mention the return of Lviv which became part of the Ukrainian SSR) was a condition for sending these activists to Lublin and Chełm.

On 16 August 1945, the border agreement was officially signed by Edward Osóbka-Morawski, on behalf of the Provisional Government of National Unity and Vyacheslav Molotov, the Soviet Minister of Foreign affairs.