The Masovia Governorate was a governorate of Congress Poland, from 1837 to 1944, with its located in Warsaw. History It was established on 7 March 1937, replacing the Masovian Voivodeship, and existed until 31 December 1844, when it was merged with the Kalisz Governorate, forming the Warsaw Governorate on 1 January 1845. Notes References Governorates of Congress Poland States and territories established in 1837 States and territories disestablished in 1844 19th century in Warsaw History of Masovian Voivodeship