Mauthausen was a Nazi concentration camp on a hill above the market town of Mauthausen, Upper Austria. It was the main camp of a group with nearly 100 further subcamps located throughout Austria and southern Germany. The three Gusen concentration camps in and around the village of St. Georgen/Gusen, just a few kilometres from Mauthausen, held a significant proportion of prisoners within the camp complex, at times exceeding the number of prisoners at the Mauthausen main camp.

From 1933 to 1945, Nazi Germany operated more than a thousand concentration camps, including subcamps on its own territory and in parts of German-occupied Europe.