This park was established to protect a strip of primary and secondary forest at 700 to 2,267 m. It holds a great diversity of animal and plant species, and guarantees a constant and clean flow for countless water sources for such important rivers as the Toro, Aguas Zarcas, Guayabo and Platanar.
As it is located in the Central Volcanic Cordillera, the area's geomorphology is volcanic. Among the main representatives is the still active Platanar volcano at 2,183 m, the inactive Cerro Viejo at 2,122, and the erosion caldera of Río Segundo.
This protected area, which is in the process of being acquired by the state, has three life zones: premontaine rain-forest, premontane wet forest and lower montane rain forest. Among the forest species are the enormous oaks (Quercus spp.), magnolia (Magnolia poasana), a species typical of the high mountains, quizarras (Ocotea spp.) and (Nectandra spp.), the yos (Sapium rigidifolium), the small cedar (Brunellia costaricensis) and the white cypress (Podocarpus macrostachyus).
The fauna is represented by 44 species of amphibians, 32 reptiles, 107 birds and 30 mammals. Among the amphibians and reptiles are the glass frog (Centrolenella euknemos), basilisk (Basiliscus plumifrons), boa (boa constrictor) and fer-de-lance (Bothrops asper.). Among the birds, the quetzal (Pharomachrus mocinno), which feeds mainly on small wild avocados, the bat falcon (Falco rufigularis) and the white hawk (Leucopternis albicollis), stand out.
The mammals include Baird's tapir (Tapirus bairdii), which is the biggest land mammal in the country, tayra (Eira barbara), northern tamandua (Tamandua mexicana), red brocket deer (Mazama americana) and coyote (Canis latrans), besides 5 of the 6 cat species in Costa Rica.
Archaeological finds indicate that the region was a meeting point for cultures form both north and south of the continent. One of the most important chiefdoms in the area before the arrival of the Spanish, was that of the Botos Indians. It extended as far as the Central Valley across the territories of the current Juan Castro Blanco and Poás Volcano National Park.
Juan Castro Blanco is situated on the Chocosuela mountain chain at the western end of the Central Volcanic Cordillera. The Naranjo - Quesada City and Quesada City - Venecia highways skirt the park to the west and north. One can see forest that is typical of the region from the road that leads to the Toro II hydroelectric project. There is a bus service between San José and Quesada. In Quesada taxis can be hired.