The Pirin Mountains are a mountain range in southwestern Bulgaria, with the highest peak, Vihren, at an altitude of 2,914 m (9,560 ft).

Rila is the highest mountain range of Bulgaria, the Balkan Peninsula and Southeast Europe. It is situated in southwestern Bulgaria and forms part of the Rila–Rhodope Massif. The highest summit is Musala at an elevation of 2,925 m which makes Rila the sixth highest mountain range in Europe after the Caucasus, the Alps, Sierra Nevada, the Pyrenees and Mount Etna, and the highest one between the Alps and the Caucasus. It spans a territory of 2,629 km2 with an average elevation of 1487 m. The mountain is believed to have been named after the river of the same name, which comes from the Old Bulgarian verb "рыти" meaning "to grub".