Karlstadt or Carlstadt (Hungarian, Károlyváros; Croatian, Karlovac), a royal free city, municipality and garrison town in the county of Agram, Croatia-Slavonia; standing on hilly ground beside the river Kulpa, which here receives the Korana and the Dobra. Pop. (1900), 7396. Karlstadt is on the railway from Agram to Fiume. It consists of the fortress, now obsolete, the inner town and the suburbs. Besides the Roman Catholic and Orthodox churches, its chief buildings are the Franciscan monastery, law-courts and several large schools, including one for military cadets. Karlstadt has a considerable transit trade in grain, wine, spirits and honey, and manufactures the liqueur called rosoglio.