Duchy of Łowicz

Księstwo Łowickie
1820–1918 (as an official entity under the name Duchy of Łowicz)

location on the map of the contemporary Łowicz and Skierniewice counties
CapitalŁowicz
DemonymKsiężaks
History 
• Established
1820
• Disestablished
1918 (as an official entity under the name Duchy of Łowicz)
Today part of Poland

The Duchy of Łowicz (Latin: Ducatus Loviciensis, Russian: Ловичское княжество, Księżak dialect: Ksinstwo) is a historical region in Poland, located in south-western Masovia, in the basin of the Bzura River, around the towns of Łowicz and Skierniewice. From the early Middle Ages until the partitions of the Polish–Lithuanian Commonwealth it was an estate of the Roman Catholic archbishopric of Gniezno. In the 19th century it belonged to the Russian tsars.

The Duchy of Łowicz retains its identity of a separate historical and cultural region inhabited by the ethnic group of Księżaks (Łowiczans) who speak the Księżak dialect of the Polish language. Their cultural distinctiveness is a result of the centuries long affiliation with the land estate.