DORNBURG, a town of Germany, in the Land of Thu ringia, situated 400 ft. above the Saale, 7 m. N.E. of Jena. Pop. 918. Dornburg is chiefly famous for its three grand-ducal castles. The Altes Schloss is built on the site of an imperial stronghold (Kaiserpfalz), once a bulwark against the Slays, often a residence of the emperors Otto II. and Otto III., and the place where the emperor Henry II. held a diet in Zoos. Goethe was often a guest at the Neues Schloss, built (1728-48) in Italian style. The third castle is the so-called Stohmannsches Rittergut, purchased in 1824 and fitted as a modern palace.