Ischigualasto Provincial Park, Provincial park in San Juan Province, Argentina

Ischigualasto is a provincial park of 60,370 hectares at about 1,300 metres in the Valle Fértil and Jáchal departments. Its grey and tan clay mounds and a tall pillar capped by a flat slab of dark grey layered rock stand before a wall of horizontal dark red and brown cliffs. The park protects the Ischigualasto Formation, whose Carnian layers hold early dinosaur remains such as Herrerasaurus and Eoraptor lunensis.

The government of San Juan Province declared Ischigualasto a protected area in 1971 after paleontologists began documenting the importance of the fossil finds. UNESCO recognized the park together with neighboring Talampaya as a World Heritage Site in 2000.

The name Ischigualasto comes from the Diaguita language and roughly translates to place without life, reflecting the barren moonscape of grey and reddish stone. Visitors today follow a marked loop that passes rock shapes named after animals or objects by local guides.

The park opens daily from 8 AM to 5 PM and offers a 40-kilometer (25-mile) loop drive with five viewpoints that must be visited with a guide. Sturdy footwear and sun protection are essential because of the intense radiation and rocky ground.

Ischigualasto holds an undisturbed sequence of Triassic rock layers that allows researchers to trace early vertebrate evolution without gaps. Some fossils are so well preserved that even skin impressions and fine bone structures remain visible.