The aim of Aktion Reinhard, decided at the secret January 20, 1942, Wansee conference of leading Nazis in Berlin, was to kill 2,284,000 Jews in Poland. Three extermination camps were constructed - Bełżec, Sobibór, Treblinka. For security reasons these had to be in isolated areas, remote from population centers, but close to railway connections. Bełżec was constructed on the Lublin-Lvov railway, and began killing operations in May 1942. Sobibór, east of Lublin, began at about the same time. Treblinka, 80 kilometers northeast of Warsaw, commenced its mass murder program on July 23, 1942. Bełżec, where 600,000 Jews were killed, was closed and dismantled in December 1942. About 250,000 Jews perished at Sobibór. During an armed uprising of prisoners on October 14, 1943, several guards were killed and 300 prisoners escaped. Immediately after that the camp was closed, and by the end of 1943, no trace of it remained. Some 870,000 Jews were murdered at Treblinka, the largest number having come from Warsaw and the Warsaw district. In an unsuccessful prisoners' revolt on August 2, 1943, nearly all the insurgents died, but the camp structures went up in flames. The grounds were plowed under, trees were planted, and the site was turned into a farm.

No mail was allowed from the Aktion Reinhard camps. This 24-groszy stamped envelope with added 32-groszy stamp was posted at Sobibór (undated three-line purple postmark) by a Nazi officer at the nearby Ossawa air base (purple cachet on flap), and canceled March 3, 1944, at Cholm, less than five months after the prisoner revolt that brought the killings there to an end.