a city and port in Sweden, on the Baltic coast, at the mouth of the Nyköping River, south of Stockholm. It is the administrative center of Södermanland. Population, 46,800 (1971). The city’s industries manufacture instruments, electrical equipment, automobiles, textiles, and wood products (prefabricated houses, furniture). The remains of a Viking settlement dating from the ninth to the 11th century have been found near the city.