The Javorniki hills are a forested karst plateau that, in a closed belt, runs from Postojna gate and Small Javornik to Mašun and Leskova Dolina. To the north it is bordered by the Unec plain, the Rak river valley, Cerknica plain, and Loška Dolina, while to the southwest lies the Pivka basin. They are mostly composed of Cretaceous limestones and interwoven with deep dolines, uvalas, chasms, and caves. They lie at elevations between 600 and 1,200 m above sea level. The highest peaks are Veliki Javornik (1,268 m), Debeli Vrh (1,273 m), and Dedna Gora (1,293 m).
