Strängnäs is a Municipality in Södermanland County, in central Sweden, located by Lake Mälaren. The municipality covers an area of 735.9 km². Of the total population of 29610, 14680 are male, and 14930 are female. The population density of the community is 40 inhabitants per km². Strängnäs Cathedral, built around 1250, is an important landmark.
