Geologically, the Zelengora range is part of the Dinaric Alps and formed largely of secondary and tertiary sedimentary rock, mostly limestone. The Zelengora range is bordered to the south-west by the Neretva river, to the east by the Sutjeska river and to the north by the Lelija range. A number of mountain lakes are scattered throughout the group, among which the beautiful Orlovačko Jezero. The Neretva river sources from these mountains: as also the Hrčavka, tributary of the Sutjeska river and the Bjelava, tributary of the Drina river. Highest peak is Bregoč (2014 m.), other notable peaks are Kozje Strane (2013 m.), Dhrtar (1970 m.), Trebova Planina (1872 m.) and Orlovača (1969 m.).