HADERSLEBEN (Danish, Haderslev), a town of Prussia, capital of a circle in the province of Schleswig-Holstein, is situated 48 miles north of the town of that name, in a pleasant valley on the Hadersleben fiord, which is about 9 miles in length and communicates with the Little Belt. The principal buildings are the beautiful church of St Mary dating from the 13th century, the theological seminary established in 1870, the gymnasium, and the hospital. The industries include iron-founding, tanning, and the manufacture of machines, tobacco, and gloves. The harbour, owing to the accumulation of mud, is only accessible to small vessels. The population in 1875, including the garrison, was 8356.

Hadersleben is first mentioned in 1228, and received town rights from Duke Waldemar II. in 1292. It suffered considerably during the wars between Schleswig and Holstein in the 15th century. In November 1864 it was ceded along with Schleswig to Prussia. Two Danish kings, Frederick II. and Frederick III., were born at Hadersleben.