Chełmno concentration camp was a Nazi extermination camp that was situated 70 km from Łódź near a small village Chełmno nad Nerem (Kulmhof an der Nehr, in German), in Greater Poland (which was, in 1939, annexed and incorporated into Germany under the name of Reichsgau Wartheland). It is not to be confused with Chełmno city (Kulm, in German).

The death camp operated from December 8, 1941 until April 1943 when it was closed down and its crematorium blown up. In spring 1944 it was reestablished and closed down again in fall 1944. A special SS Sonderkommando called Sonderkommando Kulmhof gassed people with exhaust fumes and then burnt them. The first commandant was Herbert Lange. The camp consisted of two parts: administration section, barracks and storage for plundered goods; burial and cremation site. It operated three gas vans using carbon monoxide.

It is estimated that 200,000 people were killed in the camp, mainly Jews and Gypsies from Greater Poland and Łódź Ghetto, and some Hungarian Jews, Poles, Czechs and Soviet prisoners of war.