Stormarn is a district in Schleswig-Holstein, Germany. It is bounded by (from the north and clockwise) the districts of Segeberg and Ostholstein, the city of Lübeck, the district of Lauenburg, and the city-state of Hamburg.
In medieval times the name Stormarn was applied to a larger area, of which the present-day district is only the eastern half. It was the home of the Saxon tribe the Sturmarii.
Stormarn became a part of Holstein in the 12th century. When Schleswig-Holstein became a province of Prussia in 1867, the Prussian administration established the district of Stormarn, with Wandsbek as its capital. In 1937 the southwestern part of the district was incorporated into Hamburg, and the district lost half of its population. Since Wandsbek was now a borough of Hamburg, the capital was moved to Bad Oldesloe after the war. In 1970 Stormarn again lost a substantial portion of its territory, when the city of Norderstedt was founded in order to become a part of the Segeberg district.
Stormarn may refer to:
Stormarn was a gau which, alongside Holstein and Dithmarschen, was one of the three Northern Albingian Saxon gaus.
The Gau of Stormarn lay in the southeast of Schleswig-Holstein. As well as the present county of Stormarn it also covered the territory of present-day Pinneberg, part of Steinburg, parts of Segeberg and the present land of the Hanseatic city of Hamburg north of the Elbe. The "Stormarni" were recorded in documents from the 11th century, like the Hamburg Church History (Hamburgische Kirchengeschichte) by Adam of Bremen, who appeared during the time of the attempted occupation of the Elbe estuary by Rome. The document refers to the Stormarni as one of the Saxon tribes.