Pelister National Park encompasses the northern sections of the Baba mountain massif, at altitudes ranging from 891 to 2601 metres above sea level. It covers 17,150 hectares, constituting about 43.4% of the entire mountain massif. The park features distinct geological formations from multiple geological eras, dominated by Pelister granite and green
shales from the
Ordovician and
Palaeozoic periods. Glacial and
periglacial geomorphological formations, unusual for this latitude, include
cirques,
moraines, granite block streams, and
nivation hollows, making it a unique site for geological and
geomorphological studies. Baba Mountain is the third-highest mountain range in North Macedonia and covers approximately 436 km². Geologically, the massif belongs to the western Macedonian geotectonic zone and represents the southernmost part of the Rhodope mountain system. Baba Mountain separates two major drainage basins, with rivers flowing towards the Adriatic Sea on one side and towards the Aegean Sea on the other. The park is characterized by distinctive geological and glacial features formed during the
Pleistocene epoch (about 1.8 million to 11,550 years ago). Characteristic formations are the "stone rivers" or moraines—accumulations of granite blocks and pieces of eruptive rocks like
dolerite and
gabbro, randomly piled due to repeated freezing and thawing cycles. Some of these stone rivers reach lengths up to 3 km. The park has a well-developed
hydrographic network, including numerous springs, streams, mountain rivers, and two
glacial lakes situated at elevations around 2,200 km. ==Biodiversity==