Klausenburg (Hun. Kolosvar), a town of Transylvania, capital of the county of the same name, and before 1848 of the whole country, on the Szamos, near its source, 225 m. E. by S. of Pesth, with which it is connected by railway; pop. in 1870, 26,382, chiefly Magyars. It has a fortified but partly decayed castle, and consists of two towns, the old and new, and six suburbs. It has Roman Catholic, Greek Catholic, and Protestant churches, a Roman Catholic gymnasium and seminary, a Protestant gymnasium, a Unitarian college, a Greek Catholic school, a Franciscan convent, two museums, a Hungarian theatre, and several benevolent institutions. Among the prominent buildings are several palaces belonging to the Transylvanian nobility. Klausenburg contains the only Unitarian college on the continent of Europe. In October, 1872, a university was opened here, the second in the lands of the Hungarian crown. It is an important centre of the trade between Transylvania and the neighboring counties of Hungary. It has also manufactories of porcelain. It was a colony of the Romans, belonging to the province of Dacia, and ancient coins and relics are frequently found in the vicinity. Matthias Corvinus was born here, and it has often figured in Hungarian history.

During the Hungarian revolution it was taken by Gen. Bern, Dec. 25, 1848.