Orjen comprises transboundary area of about 400 km² between Bosnia and Herzegovina and Montenegro, and runs for 25 km from region around Trebinje in Bosnia and Herzegovina in the north-west, to Bay of Kotor in Montenegro in the south-east. Mount Orjen is composed of four high karstic plateaux divided by ridges. Three near parallel ridges collide in Veliki kabao, Orjens' culmination point. The ridges are arranged by elevation with the highest to the north screening the Bijela gora plateaux from the Mediterranean coast. The separated plateaux are the Krivošije to the East, Bijela gora to the North, and Dobri do and Vrbanj to the West. Only few settlements are scattered in surrounding poljes. The poljes of Grahovo, Dragalj, Vrbanj, Krusevica and Grabalj are important for agricultural use and provide the only lines of communication in the karst. Migration circled around Mount Orjen as a major obstacle between the coastal, Herceg Novi and Risan and the interior towns of Grahovo, Trebinje and Nikšić.