Cerro Castillo National Reserve, National park and nature reserve in Aysén Region, Chile

Parque Nacional Cerro Castillo covers 143,502 hectares in the Aysén Region, split into three sectors: Lago Elizalde, Lago La Paloma and Cerro Castillo. The largest sector is crossed by the Carretera Austral up to Portezuelo Ibáñez, the divide between the Aysén and Baker river basins. Its highest peak, Cerro Castillo, rises to 2,318 m, near Cerro Las Cuatro Cumbres at 2,273 m. Lenga and ñirre woodlands cover the lower slopes.

The area became a protected reserve in 1970 and gained national park status in 2018 after efforts by the Chilean government and a conservation organization. This upgrade reflected growing recognition of the region's ecological importance.

The park's name comes from Cerro Castillo, the 2,318 m peak that dominates its largest sector. The Carretera Austral crosses this sector up to Portezuelo Ibáñez, the divide between the Aysén and Baker river basins. In 2021 The New York Times listed Cerro Castillo among destinations to visit in 2022, citing huemul conservation work by SAG, CONAF and Rewilding Chile.

A major hiking trail winds through the park and connects marked campsites with water access, requiring several days to complete. Visitors should prepare for sudden weather changes and steep elevation gains on this route.

The park sits within a conservation corridor designed to protect South Andean deer, with populations slowly growing here. These rare animals are seldom spotted, making any sighting a notable moment for visitors in this region.