The Sićevac gorge is part of the Nišava river valley, created by the intensive cutting of its water flow into the rock mass, between the northern branches of Suva Planina and the southern branches of the Svrljiške Mountains. It is located 14 km east of Niš, between the village of Prosek and the settlement of Dolac. It is about 17 km long and connects Niska with the Belopalanac basin. It is also the shortest connection between middle and lower Ponišavlje. The gorge is divided into two geographical units: the upper one (Crnčansko-Gradištanski canyon) and the lower one (Ostrovička gorge). The upper part is narrower and more similar to a canyon, while the lower part has wide gentle slopes. Due to its geomorphological features as well as unique flora and fauna, the Sićevačka gorge has been declared a nature park and a protected area with significant ecological and cultural assets.