town, län (county) of Södermanland, southeastern Sweden, on the Eskilstuna River, west of Stockholm. Although it was a trade centre as early as the 12th century, it did not receive its charter until 1659. In the 17th and 18th centuries its iron and steel industry grew rapidly, soon rivaling that of Sheffield, Eng. Eskilstuna is still one of the chief centres of the Swedish metal industry, with cutlery and precision instruments of particular importance. Mälardalen University has a branch in Eskilstuna. Pop. (2005 est.) mun., 91,635.