Area de Conservación Guanacaste World Heritage Site, Protected nature reserve in Guanacaste Province, Costa Rica

The Area de Conservación Guanacaste is a large protected nature reserve spanning about 163,000 hectares in northwestern Costa Rica that encompasses tropical dry forests, rainforests, cloud forests, and marine environments. Visitors access it through four main gateways: Santa Rosa National Park, Guanacaste National Park, Rincón de la Vieja Volcano National Park, and Junquillal Bay Wildlife Refuge.

Santa Rosa National Park, created in 1971, was the seed of the network. Over the following decades adjoining land was bought between the Inter-American Highway and the Orosí and Cacao volcanoes, and the parks were joined under SINAC in 1994. UNESCO inscribed the area in 1999, and in 2004 the site was extended by 15,000 ha of the Santa Elena rain forest.

The name Guanacaste comes from the Guanacaste tree (Enterolobium cyclocarpum), Costa Rica's national tree, whose ear-shaped pods give the province its name. The area's dry forest was largely cleared for cattle ranching before the 1970s; the park network was assembled by buying those former ranch lands and letting the forest regrow, a process researchers study as restoration in progress.

The protected area runs from the Pacific around the Islas Murciélago archipelago up over the Santa Rosa plateau to the summits of the Orosí, Cacao and Rincón de la Vieja volcanoes, then down to the Caribbean lowlands. The four national-park gateways sit at different points along this transect, so pick the one matching the habitat you want: dry forest at Santa Rosa, cloud forest and volcanoes at Rincón de la Vieja, marine and coastal habitat at Junquillal Bay.

The reserve holds an extraordinary range of plant and animal life, with thousands of plant species and hundreds of vertebrate species, many of them rare and endangered. This biological wealth makes it one of the most important places for protecting threatened wildlife across the region.