After World War II the Potsdam Conference assigned the majority of the Neumark to Polish administration , and since 1945 has remained part of Poland . Polish settlers largely replaced the expelled German population . Most of the Polish territory became part of the Lubusz Voivodeship , while the northern towns Choszczno ( Arnswalde ) , Myślibórz ( Soldin ) , and Chojna ( Königsberg in der Neumark ) belong to the West Pomeranian Voivodeship . Some territory near Cottbus , which was administratively part of the Government Region of Frankfurt ( coterminous with the Neumark ) after the 1815 Congress of Vienna , became part of East Germany in the 1940s , becoming part of Germany after reunification in 1990
Potsdam Conference
Potsdam Conference
Neumark