Mauthausen was a Nazi concentration camp on a hill above the market town of Mauthausen (roughly 20 kilometres (12 mi) east of Linz) in 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 kilometers from Mauthausen, held a significant proportion of prisoners within the camp complex, at times exceeding the number of prisoners at the Mauthausen main camp.
The Mauthausen main camp operated from 8 August 1938, several months after the German annexation of Austria, to 5 May 1945, when it was liberated by the United States Army. Starting with the camp at Mauthausen, the number of subcamps expanded over time.