Auschwitz main camp was a central hub at the heart of a number of sub-camps and locations that were deemed to be enclosed in the Interest Zone. It is worth consideration because it establishes the scale of the Nazi operation that showed slave labour as a key ingredient of a modern, industrial, slave economy.
In the words of Geoff Walden in describing Auschwitz Interst Zone:
“[The] SS appropriated an area surrounding the main camps, totalling some 15 square miles, which was called the Interessengebiet, or Interest Zone. The area between the Auschwitz I main camp and the railroad toward the northwest, in the direction of the Birkenau camp, was developed into an area of armaments factories and workshops called the Industriehof. The Krupp armaments firm had a large factory there (later operated by the Weichsel-Union-Metallwerke), and the Deutsche Ausrüstungs Werke (DAW) had several buildings of armaments workshops in the area. There were also buildings for concrete production (the camp fence posts were produced there), a central heating plant, emergency electrical generating station, bakery, a water plant, and the SS headquarters and living area. An extension camp of twenty barracks was under construction just to the north of the main camp, primarily used to house female prisoners.
Further out, the SS had housing areas and schools built, and to the south and west were the agricultural stations at Plawy, Harmense, Raisko, and Budy, with greenhouses, fish farms, cattle and pig farms, and chicken and rabbit farms, along with gravel works. Many of these latter had their own small sub-camps of the Auschwitz main camp, where prisoners were put to work grading the land, digging drainage ditches, clearing ponds, and other manual labour, as well as livestock care”.