Pirin National Park is a World Heritage national park that encompasses the larger part of the Pirin Mountains in the southwest of Bulgaria. It has an area of about 400 km² (150 sq mi) and lies at an altitude from 1,008 to 2,914 m (3,307–9,560 ft).
Two nature reserves are located within the boundaries of the park, Bayuvi Dupki-Dzhindzhiritsa, one of the oldest in the country, and Yulen.
The park's boundaries and size have stood many changes through the course of history.
Vihren National Park was created on 8 November 1962 with the purpose of preservation of the forests in the highest parts of the mountain. The park had an area of 62 km² (24 sq mi), which is a small part of its modern territory. It was renamed to Pirin People's Park in 1974 with a ministerial decree and its territory was considerably enlarged.
A separate park administration was established in 1979 with its seat in Bansko. The park was included in the UNESCO World Heritage List in 1983, and after a protected areas law was approved in 1998, the area was proclaimed a national park, embracing a territory of 403.32 km² (155.72 sq mi).