The Nadiža is a mountain stream near the town of Kranjska Gora, in the far northwestern corner of Slovenia. Springing from a bare rockface on the eastern slope of Mount Zadnja Ponca above the Tamar Valley in the Julian Alps, it is the first source of the Sava Dolinka River, the longer of the two sources of the Sava, the longest Slovene river at 221 km (137 mi) and a tributary of the Danube.