San Guillermo National Park, National park and biosphere reserve in Iglesia Department, Argentina

San Guillermo National Park is a protected area in the high Andes spanning 166,000 hectares with desert, grassland, and wetland habitats. The terrain ranges from 2,100 to 6,380 meters in elevation, creating distinct ecological zones across the mountainous landscape.

The area started as a provincial reserve in 1972 before becoming a national park in 1998. This change brought stronger protection measures for the wildlife living there.

The plain of San Guillermo was used by the Inca Empire, which arrived at the end of the 16th century, to harvest vicuña wool. Evidence of human occupation in the area goes back 10,000 years. Vicuña hair was prized for its fineness and soft texture, and both vicuñas and guanacos were hunted for it until protection took effect.

Access to many sections of the park is restricted due to safety concerns related to high elevations and severe weather. Visitors should prepare for rough mountain conditions and follow park management guidance.

In canyons and wetlands with more cover, GPS-collared vicuñas are more alert and feed less than on open plains, which shifts the plant mix and raises invertebrate numbers. Researchers also plan to collar Andean condors to see how they benefit from more vicuña kills.