Drava River, (German: Drau, drou), a major tributary of the Danube, in south-central Europe. The Drava begins in the Alps in Italy near the Austrian border and flows about 450 miles (724 km) eastward through Austria, Hungary, Slovenia, Croatia, and Yugoslavia to the Danube. The Mur is the chief tributary. Cities along the Drava include Villach, Austria; Maribor, Slovenia; and Osijek, Croatia. The Drava, including its tributaries, is used to generate hydroelectric power, especially in Austria, and for commercial barge navigation.