The Pirin Mountains are a mountain range in southwest Bulgaria, with Vihren (2,915 m high) the highest peak. The range extends about 40 km northwest-southeast, and about 25 km wide. Most of the range is protected in a national park, the Pirin National Park.
The Pirin is noted for its rich flora and fauna. Much of the area is forested, with the best conifer woods in Bulgaria, holding important populations of the Balkan endemic species Macedonian Pine, Bosnian Pine and Bulgarian Fir. Animals include the Wolf and the Brown Bear.