East Upper Silesia (German: Ostoberschlesien) is a term denoting the easternmost extremity of Silesia, that is the eastern part of the Upper Silesian region with the city of Katowice (German: Kattowitz).[1] The term is used primarily to denote those areas that became part of the Second Polish Republic on 20 June 1922, as a consequence of the post-World War I Treaty of Versailles. East Upper Silesia was annexed by Nazi Germany along with other Polish areas following the invasion of Poland in 1939 which triggered the outbreak of World War II.[1] After the war, the bulk of Silesia including East Upper Silesia became part of the People's Republic of Poland.
During the interbellum, East Upper Silesia was administered by the Second Polish Republic as Autonomous Silesian Voivodeship, hence, the East Upper Silesia was also known as Polish (Upper) Silesia, and the German (Upper) Silesia was known as the West Upper Silesia.
During the wartime annexation, the region was administered as Regierungsbezirk Kattowitz,[1] the easternmost government region of the Silesian Gau until 1941, and the eastern government region of the Upper Silesian Gau from 1941 to 1945, when Lower and Upper Silesia were administered separately. Minor parts of the former Polish areas were merged into Regierungsbezirk Oppeln, the contemporary western government region of Upper Silesia.
After the war, East Upper Silesia was restored to Poland. Currently, the region is roughly represented by the Silesian Voivodeship. Poland also received West Upper Silesia and most of Lower Silesia (see Regained Territories).