Treblinka was the second-deadliest extermination camp to be built and operated by Nazi Germany in occupied Poland during World War II. It was in a forest north-east of Warsaw, 4 km (2.5 mi) south of the village of Treblinka in what is now the Masovian Voivodeship. The camp operated between 23 July 1942 and 19 October 1943 as part of Operation Reinhard, the deadliest phase of the Final Solution. During this time, it is estimated that between 700,000 and 900,000 Jews were murdered in its gas chambers, along with 2,000 Romani people. More Jews were murdered at Treblinka than at any other Nazi extermination camp apart from Auschwitz-Birkenau.

Operation Reinhard or Operation Reinhardt was the codename of the secret German plan in World War II to exterminate Polish Jews in the General Government district of German-occupied Poland. This deadliest phase of the Holocaust was marked by the introduction of extermination camps. The operation proceeded from March 1942 to November 1943; about 1.47 million or more Jews were murdered in just 100 days from late July to early November 1942, a rate which is approximately 83% higher than the commonly suggested figure for the kill rate in the Rwandan genocide. In the time frame of July to October 1942, the overall death toll, including all killings of Jews and not just Operation Reinhard, amounted to two million killed in those four months alone. It was the single fastest rate of genocidal killing in history.