Sandanski is situated at the base of the southern slope of Pirin, one of the most beautiful mountains in Bulgaria.

Pirin is the second highest mountain in Bulgaria and with its many peaks and crystal clear lakes is great for tourism.

The Pirin Mountains ˈpirin are a mountain range in southwestern Bulgaria, with Vihren at an altitude of 2,914 m being the highest peak.

The range extends about 80 km from the north-west to the south-east and is about 40 km wide, spanning a territory of 2,585 km2. To the north Pirin is separated from Bulgaria's highest mountain range, the Rila Mountain, by the Predel saddle, while to the south it reaches the Slavyanka Mountain. To the west is located the valley of the river Struma and to the east the valley of the river Mesta separates it from the Rhodope Mountains. Pirin is dotted with more than a hundred glacial lakes and is also the home of Europe's southernmost glaciers, Snezhnika and Banski Suhodol.

The northern part of the range, which is also the highest one, is protected by the Pirin National Park, declared a UNESCO World Heritage Site in 1983. Pirin is noted for its rich flora and fauna, as well as for the presence of a number of relict species. Much of the area is forested, with some of the best preserved conifer woods in Bulgaria, holding important populations of the Balkan endemic species Macedonian pine, Bosnian pine and Bulgarian fir. Animals include many species of high conservation value, such as brown bear, gray wolf, wildcat, European pine marten, wild boar, red deer, roe deer, chamois, etc.

The combination of favourable natural conditions and varied historical heritage contribute makes Pirin an important tourist destination. The town of Bansko, situated on the north-eastern slopes of the mountain, has grown to be the primary ski and winter sports centre in the Balkans. A number of settlements at the foothills of Pirin have mineral spring and are spa resorts — Banya, Dobrinishte, Gotse Delchev, Sandanski, etc. Melnik at the south-western foothills of the mountain is Bulgaria's smallest town and is an architectural reserve. Within a few kilometres from the town are the Melnik Earth Pyramids and the Rozhen Monastery.

The name of the mountain may, according to one hypothesis, derive from Perun, the highest god of the Slavic pantheon and the god of thunder and lightning. Another version is that the etymology of the range can be traced to the Thracian word Perinthos, meaning "Rocky Mountain".

Pirin is situated in south-western Bulgaria and is part of the Rila–Rhodope Massif. To the north the Predel Saddle and mountain pass at 1140 m altitude separates it from the Rila mountain range. To the east Pirin borders the Razlog Valley, the valley of the river Mesta and the Momina Klisura Gorge that separate it from the Rhodope Mountains. To the south the Paril Saddle (1170 m) divides it from the Slavyanka mountain range. To the west Pirin reaches the valley of the river Struma, including the Kresna Gorge and the Sandanski–Petrich Valley, that serve as a divide from the Vlahina, Maleshevo and Ograzhden mountains further to the west.

The main orographic ridge extends from the north-west to the south-east. Pirin spans an area of 2,585 km2 with an average height of 1,033 m. The maximum length between the Paril and Predel saddles is 80 km; the maximum width is 40 km. Reaching an altitude of 2,914 m Pirin is the second highest mountain range in Bulgaria after Rila (2,925 m) and the eighth highest in Europe after the Caucasus, the Alps, Sierra Nevada, the Pyrenees, Mount Etna, the aforementioned Rila, and Mount Olympus.