Passau (Latin: Batavis or Batavia, also Passavium; Italian: Passavia; Czech: Pasov) is a town in Niederbayern, Eastern Bavaria, Germany, known also as the Dreiflüssestadt (City of Three Rivers), because the Danube River is joined there by the Inn River from the South, and the Ilz River coming out of the Bavarian Forest to the North.
Its population is 50,415, of whom about 10,000 are students at the local University of Passau. The university, founded in the late 1970s, is the extension of the (centuries old) Institute for Catholic Studies. It is renowned in Germany for its institutes of Economics, Law, Computer Sciences and Cultural Science.

Tourism in Passau focuses mainly on the three rivers, the St. Stephen's Cathedral (Der Passauer Stephansdom) and the "Old City" (Die Altstadt). With 17,774 pipes, the organ at St. Stephen's was long held to be the largest church pipe organ in the world and is today second in size only to the organ at First Congregational Church, Los Angeles, which was expanded in 1994. St.Stephen is a true masterpiece of Italian Baroque,built by Italian architect Carlo Lurago and decorated in part by Carpoforo Tencalla. Many river cruises down the Danube start at Passau and there is a cycling path all the way down to Vienna. It is also notable for its gothic and baroque architecture. The town is dominated by the Veste Oberhaus and the former fortress of the Bishop, on the mountain crest between the Danube and the Ilz rivers. Right beside the town hall is the Scharfrichterhaus, an important jazz and cabaret stage on which political cabaret is performed.