The Mountains of Gornjak are located in Eastern Serbia and they belong to the Carpathian-Balkan Mountains. They extend in a north-south direction and are situated between Beljanica in the south and the Homolje Mountains in the north. Thus, they represent a natural western border between Homolje and Gornja Mlava.
The Mountains are of diverse geological composition which caused the dissection of the relief by watercourses (the Mlava, the river of Breznica, the Dubočica). Moreover, this diversity causes the emphasis on vertical disunity (155 - 911 m). The Mlava River cut into the Mountains of Gornjak one of the prettiest gorges in Eastern Serbia. The regional Belgrade - Žagubica - Bor road passes through the gorge which is 16 kilometers long. Thus, these Mountains are quite well connected with traffic and are available for tourists, nature lovers, and mountaineers. The highest peak, whose altitude is 911 meters, is called “Veliki Sumurovac”. The landscape between Gornjak gorge, the village of Krepoljin, and the peak “Veliki Sumurovac” is in the shape of an undulating surface of green karst with shallow hollows, valleys, and sinkholes overgrown in places with oak-hornbeam forests. “Pogana peć”, the most stunning cave in Homolje, is located on the northern side of the Mountains of Gornjak. It is the most explored cave and the one with the greatest potential for tourist valorization. Furthermore, it is suitable for mountaineering climbing, thus, the mountaineering enthusiasts are regular guests here. The Mountains are rich in wildlife – deer, wild boar, and small game prevail.