The Holocaust in Bohemia and Moravia in the context of "Second Czechoslovak Republic"

Chełmno, or Kulmhof, was the first of Nazi Germany's extermination camps and was situated 50 km (31 mi) north of Łódź, near the village of Chełmno nad Nerem. Following the invasion of Poland in 1939, Germany annexed the area into the new territory of Reichsgau Wartheland. The camp, which was specifically intended for no other purpose than mass murder, operated from December 8, 1941, to April 11, 1943, parallel to Operation Reinhard during the deadliest phase of the Holocaust, and again from June 23, 1944, to January 18, 1945, during the Soviet counter-offensive. In 1943, modifications were made to the camp's killing methods as the reception building had already been dismantled.

At the very minimum, 152,000 people were murdered in the camp, which would make it the fifth deadliest extermination camp, after Auschwitz, Treblinka, Bełżec, and Sobibór. However, the West German prosecution, citing Nazi figures during the Chełmno trials of 1962–65, laid charges for at least 180,000 victims. The Polish official estimates, in the early postwar period, have suggested much higher numbers, up to a total of 340,000 men, women, and children. The Kulmhof Museum of Martyrdom [pl] gives the figure of around 200,000, the vast majority of whom were Jews of west-central Poland, along with Romani people from the region, as well as foreign Jews from Hungary, Bohemia and Moravia, Germany, Luxembourg, and Austria transported to Chełmno via the Łódź Ghetto, on top of the Soviet prisoners of war. The victims were murdered using gas vans. Chełmno was a place of early experimentation in the development of the Nazi extermination programme.