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.
The Mauthausen main camp operated from the time of the Anschluss, when Austria was united with Nazi Germany on 8 August 1938, to 5 May 1945, at the end of the European theatre of Second World War. Starting with the camp at Mauthausen, the number of subcamps expanded over time and by the summer of 1940 Mauthausen and its subcamps had become one of the largest labour camp complexes in the German-controlled part of Europe.
As at other Nazi concentration camps, the inmates at Mauthausen and its subcamps were forced to work as slave labour, under conditions that caused many deaths. Mauthausen and its subcamps included quarries, munitions factories, mines, arms factories and plants assembling Me 262 fighter aircraft.