The Sava has two main sources, both in the north-western, Alpine region of Slovenia. The spring of Sava Dolinka is in Zelenci near Kranjska Gora. The other leg of the river originates as Savica ("little Sava") and then flows into Lake Bohinj, which it leaves as Sava Bohinjka. Both legs meet at Radovljica, and the river is known as the Sava past that point.
The shorter, 31 km long Sava Bohinjka originates in KomarÄe, at the altitude of 805 m, from underground sources whose water comes from the valley of Triglav, the highest peak of the Julian Alps, Slovenia and former Yugoslavia.
The Sava is navigable for 593 km, from its confluence with the Danube until the mouth of the Kupa at Sisak.
The Sava represents north-western boundary of the Balkan peninsula.
The Sava Banovina or Sava Banate (Croatian: Savska banovina) was a province (banovina) of the Kingdom of Yugoslavia between 1929 and 1939.
Thereafter the boundary of this Banovina follows the river Mura, then the State frontier with Hungary to the point where this leaves the Drava; from this point the boundary of the Banovina follows the course of the Drava, then that of the Danube, as far as the northern boundary of the district of Ilok.
It then follows the course of the riverSava to the mouth of the riverUna, then the course of the riverUna as far as the north-eastern boundary of the district of Dvor (south-west of Kostajnica).