Notes

Hostage camps: camps where hostages were held and killed as reprisals.
Labor camps: concentration camps where interned inmates had to do hard physical labor under inhumane conditions and cruel treatment. Some of these camps were sub-camps of bigger camps, or "operational camps", established for a temporary need.
POW camps: concentration camps where prisoners of war were held after capture. POWs were usually soon assigned to labor camps.
Camps for rehabilitation and re-education of Poles: camps where the intelligentsia of the ethnic Poles were held, and "re-educated" according to Nazi values as slaves.
Transit and collection camps: camps where inmates were collected and routed to main camps, or temporarily held (Durchgangslager or Dulag).
Extermination camps: These camps differed from the rest, since not all of them were also concentration camps. Although none of the categories is independent, and many camps could be classified as a mixture of several of the above, and all camps had some of the elements of an extermination camp, systematic extermination of new-arrivals occurred in very specific camps. Of these, four were extermination camps, where all new-arrivals were simply killed – the "Aktion Reinhard" camps (Treblinka, Sobibor and Belzec), together with Chelmno. Two others (Auschwitz and Majdanek) were combined concentration and extermination camps.