Iskar (in ancient Greek: Oescus, Eskus) is a river in Bulgaria, Sofia District, Vratsa, Lovech and Pleven, right tributaries of the Danube.
Its length is 368 km, along with the Beli Iskar River, which ranks 2nd in the rivers of Bulgaria. The length of the Iskar River is 340 km.
Iskar is the longest entirely Bulgarian river.
After passing through it and flowing from Iskar reservoir between the mountains Vitosha and Plana to the west and the Lozen Mountain to the east, it forms the deep and picturesque Pancharevo Gorge (22 km).
The Iskar River springs from Rila Mountain and is formed by the merging of the rivers Cherni Iskar (left) and Beli Iskar (right), 500 m north of the village of Beli Iskar, 1 047 m above sea level. Immediately afterwards it enters the Samokov valley.
After leaving the Pancharevo dam, the river enters the Sofia Field, passing the eastern districts of Sofia and in the town of Novi Iskar enters the majestic Iskar Gorge (about 65 km).
After the village of Lutybrod, Iskar leaves the Stara Planina mountain, continues eastwards and its valley is expanding.