The Ogosta is the largest river in Northwestern Bulgaria, a right tributary of the Danube. It originates at Chiprovska Mountain, 2,168 meters high section of the Western Balkan Mountains, at about an altitude of 1,760 meters, on the border with Serbia. The towns of Chiprovtsi, Montana, and Miziya are situated on the rivers banks.
The Ogosta river is 147.4 km in length and is fed by 40 tributaries (including the Skat River) in a watershed of 3,157 square kilometers. The average water discharge in the lower course of the river is 18 cubic meters per second. Along the river there are 14 irrigation systems, 8 hydropower plants, and 13 dams.
