Eskilstuna is a city and the seat of Eskilstuna Municipality, Södermanland County, Sweden. The city of Eskilstuna had 69,948 inhabitants in 2020, with a total population of 107,806 inhabitants in Eskilstuna municipality 2023. Eskilstuna has a large Sweden Finn population. The town is located on the River Eskilstunaån, which connects Lake Hjälmaren and Lake Mälaren.

Södermanland County is a county or län on the southeast coast of Sweden. In the local Sörmlandic dialects it is virtually universally shortened and pronounced as Sörmlands län, or simply Sörmland, which is the dominant pronunciation and spelling inside the county. For example, the name of the local regional council is Region Sörmland. It borders the counties of Östergötland, Örebro, Västmanland, Uppsala, Stockholm and to the Baltic Sea. It holds the popular camping route called "Sörmlandsleden" which is a system of trails covering a total of approximately 100 mil (1000 km) of walking paths, in Södermanland. Prince Alexander, the son of Prince Carl Philip, is Duke of Södermanland.