The name Prenj is derived from Perun, supreme deity of Slavic mythology. Geologically, the Prenj range is part of the Dinaric Alps and formed largely of secondary and tertiary sedimentary rock, mostly limestone and dolomite with notable characteristics of a karst landform. Due to subterranean drainage, Prenj is relatively dry with few water sources, just a few tiny lakes and some smaller streams that source from these mountains: the Baščica and the Bijela, tributaries of the Neretva.