Nanos is a high karst plateau in a mountain barrier that separates the continental part of Slovenia from the Littoral. It is a 12 km long and up to 6 km wide karst plateau with a steeply cut edge called Pleša. Next to Snežnik is the most typical mountain in the Notranjska region.
The forested plateau is visited by mountaineers and paragliders. The deposit is crossed by the Slovenian Mountain Transversal and the Slovenian Geological Trail. There is a television converter at the Pleša lookout point (1262 m), and Vojkova koča is nearby.
The highest level rises in the northern part, where the highest peaks are Suhi vrh (1313 m) and Debeli vrh (1301 m). Pleša has a view and because there is a mountain lodge below the top, it is the most visited. The Nanos is dominated by Cretaceous limestones, the surface is rocky and karst dissected. The sediment is mostly covered with spruce forests, only in the southern part there are extensive grassy areas. At the southern edge of the plateau above the Vipava Valley, in the upper part, there are bare, cut-off steep slopes, which pass towards the valley into a gentler forested slope. There are 30 larger and smaller abysses on Nanos, the most famous are the two "ice halls", the Great Vipava Glacier and the Slapen Glacier.
The view from Pleša is beautiful. On the east side lies the Postojna basin with Postojna on the extreme edge and Javorniki above it, and behind it are the peaks from the Crimea to the Posavje hills, Gorjanci and Kočevski Rog. In the southeast there are extensive Snežnik forests, above which Snežnik rises; behind are the peaks of Gorski Kotar. In the south, at the transition from the Postojna basin to the Vipava valley, just below us is Razdrto, behind it rise the Senožeški hills and Vremščica, and to the right is a view across the Karst to the Gulf of Trieste. On the west side we see the edge of Nanos, which falls into the Vipava Valley, Vipava, Ajdovščina and Čaven in the north and the plateau of the Trieste-Comenius Karst with Trstelj on the south side of the Vipava Valley. In the north there are extensive forests of Nanos, Hrušica and Trnovski gozd, and behind them rise the Julian Alps, Karavanke and Kamnik Alps.