HADERSLEV, a town of Denmark in the province of North Slesvig. Pop. (1925) 14,326. It lies in a valley on the Haders leben fjord, which is about 9 m. in length, and communicates with the Little Belt, and is also an important railway junction. The beautiful church of St. Mary dates from the i3th century. The industries are iron-founding, tanning, and the manufacture of tobacco and gloves. The harbour is only accessible to small vessels.
Haderslev is first mentioned in 1228, and received municipal rights from Duke Waldemar II. in 1292. It suffered considerably during the wars between Slesvig and Holstein in the 15th cen tury. In Nov. 1864 it passed with Slesvig to Prussia, returning to Denmark with North-Slesvig by the plebiscite held in 192o under the terms of the Treaty of Versailles.