Following Nazi Germany's defeat in World War II in 1945, East Prussia was partitioned between Poland and the Soviet Union according to the Potsdam Conference. Southern East Prussia was placed under Polish administration, while northern East Prussia was divided between the Soviet republics of Russia (the Kaliningrad Oblast) and Lithuania (the constituent counties of the Klaipėda Region). The city of Königsberg was renamed Kaliningrad in 1946. The German population of the province largely evacuated during the war, but several hundreds of thousands died during the years 1944–46 and the remainder were subsequently expelled.

What two countries were East Prussia partitioned into after World Was II?