HEILIGENSTADT, a town of Prussian Saxony, government district of Erfurt, is situated on the Leine and on the railway from Halle'to Cassel, 32 miles E.N.E. of Cassel. It possesses an old castle, formerly belonging to the electors of Mainz, one Evangelical and two Catholic churches, a Catholic gymnasium, a Catholic normal school, two orphanages, and an infirmary. The principal manufactures are woollen wares, cigars, paper, bone dust, and needles. The population in 1875 was 5193.

Heiligenstadt is said to have been built by Dagobert, and was formerly the capital of the principality of Eichsfeld. In 1022 it was acquired by the archbishop of Mainz, and in 1103 it came into the possession of Henry the Proud, but when Henry the Lion was placed under the ban of the empire it again came to Mainz. It was destroyed by fire in 1333, and was captured in 1478 by Count Henry the Young of Schwarzburg, and in 1525 by Duke Henry of Brunswick. In 1803 it came into the possession of Prussia.