Eskilstuna, city in southeastern Sweden, between Lakes Mälaren and Hjälmaren, near Stockholm, in Södermanland County. Eskilstuna is called the Sheffield of Sweden because of its iron and steel industries and fine cutlery. Other products are machinery, machine tools, and a type of ornamented steel called damascened steel. A large arms factory is located on an island in Lake Hjälmaren. Eskilstuna maintains a technical school for training in the metal industries. The city is named after Saint Eskil, an 11th-century English missionary believed to have been martyred in the settlement. Population (1998 estimate) 98,261.