Klosterneuburg (klôs'tərnoi`bo͝orkh), city (1991 pop. 24,442), Lower Austria prov., NE Austria, on the Danube River and the north slope of the Wienerwald, near Vienna. Klosterneuburg was port of Vienna from 1938 until 1954, when it was returned to Niederöstereich. It is the site of a wealthy Augustinian monastery (consecrated 1136), the oldest in Austria. The monastery has an extensive library, enormous wine cellars, and the famous Verduner Altar (1181) by Nicholaus of Verdun. Klostenburg is also home to the Federal College of Viticulture and Pomology (1860), one of the only schools in the world with a focus on wine-making. It is a popular river resort, and has wood and chemical manufacturers.