The excavations conducted on the Swedish prehistoric hillforts are very limited. However, a lot of people are drawn to them because of their impressive size, which include preserved walls that can reach over three metres in height. They are frequently associated with legends about giants who once lived there. The majority of the hillforts in Sweden were built during the Roman Iron Age and the Migration period. The purpose for which the hillforts were built has been the subject of intense debate, but it is now generally accepted that not every hillfort would have served the same function. The goal of this thesis is to map the hillforts in Eskilstuna municipality, Södermanland County, in order to better understand their purpose, their topographic locations, and the number of other hillforts that could have been seen from each hillfort. This will primarily be achieved through literature reviews of prior studies on the topic and the use of GIS.