Dena is the name for a sub-range within the Zagros Range of West/Southwestern Iran . Mount Dena , with 80 km length and 15 km average width , is situated on the boundary of the Isfahan , Kohgiluyeh and Boyer-Ahmad and Chaharmahal and Bakhtiari provinces .
Mount Dena has more than 40 peaks higher than 4000 metres . With an elevation of 4,409 metres above sea level , Qash-Mastan is the highest peak in the Dena Range and in the Zagros Mountains in general . Another famous peak in this range is Hose-Daal close to Sisakht city , 30 km to the north of Yasuj .
Annual precipitation in Mount Dena is from 600 to 1800 mm and various rivers including a branch of the Karun rise in this range .
Geologically , Mount Dena is located in the Sanandaj-Sirjan geologic and structural zone of Iran and is mainly made of cretaceous limestone .