Situated in the Kuyavian-Pomeranian Voivodship (since 1999), previously in Torun Voivodship (1975-1998).
The first written mention about Chelmno is known from a document allegedly issued in 1065 by Polish duke Boleslau I of Poland for the Benedictine Monastery in Mogilno. In 1226 Prince Konrad of Mazovia brought Teutonic Knights to Chelmno Land. In 1233 Chelmno was granted the location privilege called "Chelmno rights" (renewed in 1251), the model system for over 200 Polish towns. The town of Chelmno together Chelmno Land was part of Teutonic Knights state untill 1466, when after Thirteen-Year-War Chełmno was incorporated back into Poland. In 1772 following partitions of Poland Chelmno became part of Kingdom of Prussia. Between 1807 and 1815 Chelmno was part of Duchy of Warsaw. Chelmno was recovered by Poland in 1920.