File:Podzial Ks Warszawskiego na departamenty.png
Administrative division of the Duchy of Warsaw, 1810–1815. Siedlce Department is red in the center-east.
Siedlce Department (Polish: Departament siedlecki) was a unit of administrative division and local government in Polish Duchy of Warsaw in years 1809–1815.
Its capital city was Siedlce, and it was further divided onto 9 powiats.
In 1815 it was transformed into Podlasie Voivodeship.