Husum (North Frisian: Hüsem) is the capital of the Kreis (district) Nordfriesland in Schleswig-Holstein, Germany. The town was the birthplace of the novelist Theodor Storm, who coined the epithet "the grey town by the sea". It is also the home of the annual international piano festival Raritäten der Klaviermusik (Rarities of Piano Music) founded in 1986.
Husum was first mentioned as Husembro in 1252, when king Abel was murdered.
Like most towns on the North Sea, Husum was always strongly influenced by storm tides. In 1362 a disastrous storm tide, the "Grote Mandrenke" flooded the town and carved out the inland harbour. Before this date Husum was not situated directly on the coast. The people of the city took advantage of this opportunity and built a marketplace, which led to a great economic upturn.
Between 1372 and 1398 the population of Husum grew rapidly, and two villages, Oster-Husum (East-Husum) and Wester-Husum(West-Husum), were founded.
The name Husum is first mentioned in 1409.It is shown on the Carta Marina in the Frisian form of Husem.