The Pirin Mountains are a mountain range in southwestern Bulgaria, with Vihren (2,914 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.
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.
The town of Bansko, an important tourism and winter sports centre, is situated on the northeast slopes of the Pirin Mountains. The town of Razlog lies in a valley between Pirin to the south and the Rila Mountains to the north.
Pirin is the second highest mountain in Bulgaria after Rila (2,925 m) and the sixth highest in Europe after the Caucasus, the Alps, Sierra Nevada, the Pyrenees, Mount Etna and the aforementioned Rila when each is represented by its highest peak only. It has an area of 2,585 km and an average height of 1,033 m. Pirin is set in the southwest of the country between the Struma and Mesta Rivers, bordering Rila to the north at the Predel Saddle (1,142 m) and Slavyanka to the south at the Parilska Saddle (1,170 m). The distance between these two points is 60 km from the northwest to the southeast and the maximum width of Pirin is 40 km from the town of Sandanski to the village of Obidim. Other neighbouring mountains include Vlahina, Maleshevo, Osogovo and Ograzhden to the west, as well as the Rhodopes to the east.