WSubdivisions of the Duchy of Warsaw were based on departments that were headed by prefects. The subsidivions were based on the French model following the erection of the Duchy of Warsaw by Napoleon. The departments were in turn subdivided into traditional Polish powiats (counties). Initially six departments were created out of the province of South Prussia in the Kingdom of Prussia. After the 1809 Polish–Austrian War, and the Treaty of Schönbrunn, their number increased to ten. Each department was named after its capital city.
WBydgoszcz Department was a unit of administrative division and local government in Polish Duchy of Warsaw in years 1806–1815.
WKalisz Department was a unit of administrative division and local government in Polish Duchy of Warsaw in years 1807–1815.
WKraków Department was a unit of administrative division and local government in Polish Duchy of Warsaw in years 1809–1815.
WŁomża Department was an administrative division and local government in the Polish Duchy of Warsaw in the years 1807–15. The Department comprised 10 counties and had its capital at Łomża.
WThe Lublin Department was a unit of administrative division and local government in Polish Duchy of Warsaw in years 1810-1815. Its capital was Lublin. The division contained 10 counties. In 1815 it was transformed into the Lublin Voivodeship.
WPłock Department was a unit of administrative division and local government in the Polish Duchy of Warsaw from 1806 to 1815.
WPoznań Department was a unit of administrative division and local government in Polish Duchy of Warsaw in years 1806-1815.
WRadom Department was a unit of administrative division and local government in Polish Duchy of Warsaw in years 1809–1815.
WSiedlce Department was a unit of administrative division and local government in Polish Duchy of Warsaw in years 1809–1815.
WWarsaw Department was a unit of administrative division and local government in Polish Duchy of Warsaw in years 1806–1815.