Nordhaisen, a town of Prussia, in tin province of Saxony, 38 m. N. W. of Erfurt, an the S. extremity of the Hartz mountains; pop. in 1871, 21,273. It consists of an old or upper town, a new or lower town, and several suburbs. The first is situated on a hill, and contains the town hall, the market, and the principal churches. There are seven Protestant churches and a Roman Catholic cathedral. In the church of St. Blasius are two famous paintings by Lucas Oranach. Nordhausen contains over 50 brandy distilleries and many breweries. The fattening of cattle is a prominent industry, and the town is the centre of the corn trade of the region. Near it are the castles of Hohen-stein and Ebersburg. - The wife of the emperor Otho I. founded a monastery here in the 10th century. Several diets were held here in the 11th and 12th centuries, and in the 13th Nord-hausen became an imperial city, belonging to the circle of Lower Saxony. In 1802 it was allotted to Prussia; in 1807 it formed part of the kingdom of "Westphalia, but was restored to Prussia in 1813.