Eisenberg (Isenberg), a town of Germany, in the duchy of Saxe-Altenburg, on a plateau between the rivers Saale and Elster, 20 m. S.W. from Zeitz, and connected with the railway Leipzig-Gera by a branch to Crossen. Pop. (1905) 8824. It possesses an old castle, several churches and monuments to Duke Christian of Saxe-Eisenberg (d. 1707), Bismarck, and the philosopher Karl Christian Friedrich Krause (q.v.). Its principal industries are weaving, and the manufacture of machines, ovens, furniture, pianos, porcelain and sausages.
See Back, Chronik der Sladt und des Amtes Eisenberg (Eisenb., 1843).