The Sava river is 945 km long, originating from the merging of the rivers Sava Dolinka (which rises near the town of Kranjska Gora) and the Sava Bohinjka (rising south of the mountain of Triglav) near Radovljica in Slovenia. It flows into the Danube in Belgrade. The Sava is navigable by river boats from Sisak in Croatia to Belgrade.
It flows through four countries: Slovenia, Croatia, Bosnia and Herzegovina and Serbia. Its largest tributaries in Serbia are the Drina and the Kolubara. Major cities located on the Sava in Serbia are Sremska Mitrovica, Šabac and Belgrade.
The total area of the Sava basin is 97,713 km2. Measured by length it is the third largest and by flow rate the largest tributary of the Danube. The Sava is also of great importance to the Danube basin because of its exceptional biological and geological diversity. Four Ramsar sites have been designated in the Sava basin: the Cerkniško Jezero lake (Slovenia), Lonjsko Polje (Croatia), Bardača (Bosnia and Herzegovina) and Obedska Bara (Serbia). It also harbours numerous other important habitats for birds and plants, as well as protected regions of national interest.