Dena`s the highest mountain of Zagros sierra, located in the west of Iran the western part of Persian plateau. Peaks of Dena are higher than 4000m and the most higher one is Bijan3 that the height is 4409m and it`s located in the northwest of Yasouj at the distance of 35 km.
Sisakht city, the center of Dena, have been located in the mountainside of Dena. In the other hand, there are many valleys with small fountains on the mountainside. Also protected zone of Dena is one of the habital stores in the north of Kohgiloye-o- Boyerahmad and south of Isfahan.