EISENBERG, a town in the west circle of the duchy of Saxe-Altenburg, and 24 miles W.S.W. of Altenburg. It is very old, and has changed possessors more than once, but was joined to Saxe-Altenburg in 1826. It possesses an old castle and a beautiful church. Its industries are principally woollen and porcelain manufactures, linen-weaving, and shoe-making. Population in 1875, 5509.