Bialystok District

Bialystok District (German: Bezirk Bjelostock) was an administrative unit of Nazi Germany created during the World War II invasion of the Soviet Union. It was to the south-east of East Prussia, in present-day northeastern Poland as well as in smaller sections of adjacent present-day Belarus and Lithuania. It was sometimes also referred to by the designation South East Prussia (German: Südostpreußen - see the map below) along with the Regierungsbezirk Zichenau, although in contrast to the latter, it was not incorporated into, but merely attached to East Prussia.

The territory lay to the east of the Molotov–Ribbentrop line and was consequently occupied by the Soviet Union and incorporated into the Byelorussian Soviet Socialist Republic. In the aftermath of the German attack on the Soviet Union in June 1941, the westernmost portion of Soviet Belarus (which, until 1939, belonged to the Polish state), was placed under the German Civilian Administration (Zivilverwaltungsgebiet). As Bialystok District, the area was under German rule from 1941 to 1944 without ever formally being incorporated into the German Reich.

The district was established because of its perceived military importance as a bridgehead on the far bank of the Neman. Germany had desired to annex the area even during the First World War, based on the historical claim arising from the Third Partition of Poland, which had delegated Białystok to Prussia from 1795 to 1806 (see New East Prussia). In contrast to other territories of Eastern Poland which were permanently annexed by the Soviet Union following the Second World War, most of the territory was later returned to Poland.