The Nishava River springs from the Golyamo Mochurishte area, about 0.6 km west of Malak Kom Peak (1959 m high), in the Western Stara Planina. In its upper course, the river is known as the Ginska River. This is the reason why, mainly in Serbia, it is believed that Nishava originated only after the confluence of Ginska and the Erma River on Serbian territory, near the village of Sukovo. There is a third version of the sources of the river, adopted by some travelers in the past (Irechek, Konstantin. Travels in Bulgaria, Sofia 1974, p. 546), according to which, the beginning of Nishava comes from the river Ezhevitsa, which springs not far from Dragoman.
Near the village of Gintsi, the Nishava River flows into a deep valley, after which it continues its way through the Godech valley. In its gorge, near the village of Razboishte, is hidden a unique masterpiece of Bulgarian spirituality and culture - the rock monastery "Introduction to the Mother of God", and shortly before the beginning of the village of Kalotina its waters have carved a picturesque gorge.
The Nishava River has mainly karst underground recharge and is one of the Bulgarian rivers with the largest surface runoff (on arrival). Near the village of Kalotina the river is full of water in the months of February-April and low water in August-September. It freezes on average for about 30-40 days a year.
After leaving Bulgaria, the Nishava River passes through the Tsaribrod and Pirot fields, where the Temska River flows into it. After Bela Palanka the river forms the impressive Sichevska gorge. In Serbia, Nishava crosses the towns of Tsaribrod, Pirot, Bela Palanka, Niska Banya and Nis. The total length of the river on Serbian territory is 151km.
The catchment area of Nishava in Bulgaria is 191 sq. Km and its length is 40 km. The average annual outflow at Kalotina is 1.80 cubic meters per second.