HAINBURG, or HAIMBURG  , a town of Austria, in Lower Austria, 38 in . E.S.E of Vienna by rail . Pop . (1900), 5134 . It is situated on the Danube, only 22 M. from the Hungarian frontier, and since the fire of 1827 Hainburg has been much improved, being nowaa handsomely built town . It has one of the largest tobacco manufactories in Austria, employing about 2000 hands, and a large needle factory . It occupies part of the site of the old Celtic town Carnuntum (q.v.) . It is still surrounded by ancient walls, and has a gate guarded by two old towers . There are numerous Roman remains, among which may be mentioned the altar and tower at the town-house, on the latter of which is a statue, said to be of Attila . A Roman aqueduct is still used to bring water to the town . On the neighbouring Hainberg is an old castle, built of Roman remains, which appears in German tradition under the name of Heimhurc; it was wrested from the Hungarians in 1042 by the emperor Henry III . At the foot of the same hill is a castle of the 12th century, where Ottakar of Bohemia was married to Margaret of Austria in 1252; earlier it was the residence of the dukes of Babenberg .

Outside the town, on an

island in the Danube, is the ruined castle of Rothelstein or Rothenstein, held by the Knights Templars . Hainburg was besieged by the Hungarians in 1477, was captured by Matthias Corvinus in 1482, and was sacked and its inhabitants massacred by the Turks in 1683 .