Sinjajevina is a spacious and high mountain of 35-40 km long and 10-15 km wide. It is the highest limited space between the high mountains of Montenegro. There is a large number mountain reefs about 1,700m rising form the extensive mountain surface, among which 6 of them are over 2,000m high. The highest of them are: Vranova glava - Rook head (2215 m) and Babin zub (2253 m).
The rivers Plasnica, Štitarička river and Bistrica, the left tributary of the river Tara, flow through the east and southeast side of Sinjajevina. Numerous coves that are almost equally distributed throughout the mountain represent a special feature of karst terrain of Sinjajevina. About 90% of the territory of Sinjajevina is covered by meadows and pastures, so Sinjajevina represents the most spacious pasture area in Montenegro. Only the northwestern and southeastern part of the mountain are covered by dense coniferous and beech forests.