The government region was created on 26 October 1939, out of Polish areas annexed by Nazi Germany during World War II.
The region had an area of 12,000 km2 and a population of approximately 895,000, including 800,000 Poles, 80,000 Jews, and 15,000 Germans.
The Polish population was subjected to various crimes, including mass arrests, roundups, deportations to forced labour and concentration camps (including teenagers),[2][3] executions, massacres (also as part of the Intelligenzaktion and Aktion T4) and expulsions.
[4][5][6] The Germans operated jails and prisons in Ciechanów, Mława, Ostrołęka, Płock, Płońsk, Przasnysz, Pułtusk, Sierpc.
[9] Regierungsbezirk Zichenau was dissolved in 1945 when East Prussia was overrun by the Soviet Red Army.