Concentration camp located near an unused stone quarry about three miles from the town of Mauthausen in Upper Austria. Mauthausen commenced functioning in August 1938, a few months after the Anschluss [the annexing of Austria by Germany.] The first prisoners to arrive were forced to build the camp and work in the quarry. The work in the quarry proved deadly for many inmates.
During its initial year, the 1,100 prisoners brought to Mauthausen were common criminals, people deemed "asocial" and unfit to live in German society.  Additionally, political opponents of the Reich, including a group of political prisoners transferred from Dachau – were brought to Mauthausen. Throughout the war, the camp was mainly used for political or ideological opponents of the Nazi regime.
Mauthausen was divided into three sections: the prison camp, administrative area and SS housing. The prison camp was Mauthausen's main area, and was made up of 3 sections. Prisoners lived in the 20 huts of Camp No. 1. Each hut was built to hold 300 prisoners, but in most cases more than 600 were forced into the space. Four of the huts were quarantine huts, where new prisoners lived for 3 weeks. Afterwards, they were moved into other huts. Camp No. 2 was a workshop area, which contained 4 huts. From the beginning of 1944, it was also used as a quarantine area. Camp No. 3, built in the spring of 1944, originally contained six huts. Beginning in the summer of 1944, sick and weak prisoners were brought there prior to being killed.
The camp complex was guarded by the brutal SS “Death's Head Units”. Prisoners held various positions of authority such as; camp elder, the elder's deputies and camp registrar. The work in the camp was overseen by Kapos whilst the camp blocks were handled by the block elder, block registrar, and room elders. All prisoners in positions of authority were given special privileges.
Until World War II broke out, Mauthausen was similar to other concentration camps in Germany. German prisoners were incarcerated for harsh forced labor but the conditions at the camp were not as brutal as they would become later. When the war began, things changed at Mauthausen. It expanded to become both a concentration camp and a killing center for political and ideological opponents from within the Reich and from other Nazi-occupied countries. Food rations were decreased and the prisoners lived in extremely crowded and unsanitary conditions. This led to the outbreak of typhus and dysentery epidemics, weakening and killing many.
By the end of 1939, the camp had more than doubled its prisoner population to 2,666. During 1940, the number of prisoners arriving grew exponentially. About 11,000 new inmates were sent to Mauthausen, leading the camp authorities to establish the first of several satellite camps nearby. Among the prisoners who arrived in 1940 was a group of Republican Spaniards who had fled Spain after General Francisco Franco won the Spanish Civil War. They had sought refuge in France only to be arrested there by the Nazis after the German invasion in May 1940.
A total of 18,000 new prisoners arrived at Mauthausen in 1941, including the camp's first group of Jews, who came in May from the Netherlands. Other new arrivals included many new Spanish prisoners, Czech political prisoners, and more than 4,000 Soviet prisoners of war. Most of the Czech prisoners were murdered that summer, in retaliation for the death of SS leader Reinhard Heydrich at the hands of Czech resistance fighters. The Soviet prisoners lived in separate huts called the "Russian camp." Despite the large number of incoming prisoners, there were only 11,135 left by the end of 1941 due to the camp's extremely high mortality rate.
In 1942, prisoners continued to arrive from the Netherlands, the Soviet Union, Czechoslovakia and Yugoslavia. Additionally, transports arrived from France, Belgium, Greece, and Luxembourg. During 1943, 21,028 new internees arrived from all over Europe. Only a few were Jews. That year, more than 8,000 prisoners died in Mauthausen and its sub-camp, Gusen.
A large number of new prisoners arrived in 1944. Consequently, the German authorities ordered the construction of several satellite camps to control the overflow. Altogether, more than 65,000 new prisoners were recorded, and the maximum population that year was 114,524. In May 1944, Mauthausen admitted large transports of Jews from Auschwitz. The number of Jews who died in Mauthausen that year topped 3,000. Many groups of Poles also arrived in Mauthausen in 1944, after the Warsaw Polish Uprising was suppressed, in October 1944. Many Polish students and underground members were killed soon after they arrived.
Almost 25,000 new prisoners came to Mauthausen in 1945, including a stream of Jewish prisoners from Hungary who had been previously interned in camps along the Austrian-Hungarian border, and forced to build a line of fortifications. As the battlefront drew closer, their camps were emptied out and the prisoners were marched on foot to Mauthausen. Many died en route.
The Jews interned in Mauthausen were treated much worse than the other prisoners. They were forced to dig tunnels at the sub-camps for underground ammunition factories and were expected to do so at an unbearably fast pace. After a month or so, the Jewish workers were so physically broken and exhausted they could hardly move.
On May 3, 1945, a police unit from Vienna took over the camp's security. The next day, all work stopped at the camp and the SS officers left. On May 5, American troops arrived and liberated the camp. Altogether, 199,404 prisoners passed through Mauthausen. Approximately 119,000 of them, including 38,120 Jews, were killed or died from the harsh conditions, exhaustion, malnourishment and overwork.  Furthermore, the sick, weak and "undesirable" prisoners were taken to the nearby Hartheim Castle to be exterminated in the gas chamber during the periods of August 1941 to October 1942 and April to December 1944.