Russian-occupied Eastern Poland

Occupation of Poland by Germany and the Soviet Union
Beginning of Lebensraum, the German expulsion of Poles from central Poland, 1939
Operation Tannenberg, October 1939, mass murder of Polish townsmen in western Poland
1939–1941
Fourth Partition of Poland – aftermath of the German-Soviet Pact; division of Polish territories in the years 1939–1941 prior to the German attack on the Soviet positions in Poland
1941–1945
Changes in administration of occupied Polish territories following the German attack on the Soviet positions in 1941. The map shows district divisions in 1944

The occupation of Poland by Nazi Germany and the Soviet Union during the Second World War (1939–1945) began with the German-Soviet invasion of Poland in September 1939, and it was formally concluded with the defeat of Germany by the Allies in May 1945. Throughout the entire course of the foreign occupation, the territory of Poland was divided between Germany and the Soviet Union (USSR) with the intention of eradicating Polish culture and subjugating its people by occupying German and Soviet powers. In summer-autumn of 1941 the lands annexed by the Soviets were overrun by Germany in the course of the initially successful German attack on the USSR. After a few years of fighting, the Red Army was able to repel the invaders and drive the German forces out of the USSR and across Poland from the rest of Central and Eastern Europe.

Both occupying powers were equally hostile to the existence of sovereign Poland, Polish culture and the Polish people, aiming at their destruction. Before Operation Barbarossa, Germany and the Soviet Union coordinated their Poland-related policies, most visibly in the four Gestapo-NKVD Conferences, where the occupants discussed plans for dealing with the Polish resistance movement and future destruction of Poland.

About 6 million Polish citizens—nearly 21.4% of Poland's population—died between 1939 and 1945 as a result of the occupation, half of whom were Polish Jews. Over 90% of the death toll came through non-military losses, as most of the civilians were targeted by various deliberate actions by Germans and the Soviets. Overall, during German occupation of pre-war Polish territory, 1939–1945, the Germans murdered 5,470,000–5,670,000 Poles, including nearly 3,000,000 Jews.