Södermalm is a city district area (Swedish: stadsdelsområde, often referred to as a borough) in central Stockholm, Sweden.

[1] The urban development project of Hammarby Sjöstad is located in the Södermalm borough.

[2] Södermalm was created 1 January 2007, through the merging of the boroughs of Maria-Gamla Stan and Katarina-Sofia.

The two former boroughs made up the eastern and western half of the island of Södermalm.

Maria-Gamla Stan also included the island districts of Gamla Stan, Långholmen, Reimersholme, Riddarholmen and Årsta holmar; Katarina-Sofia included the district Södra Hammarbyhamnen south of Södermalm.