Warthegau

After the German invasion of Poland on 1 September 1939, occupied Poland was dividd into three zones, the westernmost being called the Warthegau, Reichsgau Posen or sometimes Wartheland. As opposed to the Generalgouvernement in Central Poland, treated a colony, or the eastern part under Soviet control, the Warthegau was absorbed into the Reich and "Germanized". It was the largest administrative unit in the Reich, covering a total of 16,966 square miles. At the beginning of World War II, 4,922,000 people lived in the area, including 385,000 Jews and 325,000 Germans.

Germanization, directed by the Gauleiter, Arthur Greiser, encouraged both ethnic Germans already in the area, as well immigration by Germans. In contrast, most Polish property was confiscated, many Poles deported, especially Polish Jews. The latter rarely survived.

Wilhelm Koppe was the original HSSPF, until he became HSSPF of the Generalgouvernement in 1943.