El Triunfo Biosphere Reserve has an area of 1191.77 km2 in the Sierra Madre de Chiapas, a mountain range that extends roughly east–west parallel to the Pacific coast of Mexico and Guatemala.

To the west El Triunfo borders the Zona de Protección Forestal en los terrenos que se encuentran en los municipios de La Concordia, Angel Albino Corzo, Villa Flores y Jiquipilas a natural resources protection area that protects the northern slope of the Sierra.

El Triunfo, the Zona de Protección Forestal, and La Sepultura Biosphere Reserve further to the west form a continuous protected corridor along the western Sierra.

[2] El Triunfo is notable for its cloud forests, which occur in mountain areas with high year-round rainfall.

The cloud forests' vegetation and soils absorb the mountains' high rainfall, releasing it slowly into the rivers that drain from the mountains to the Pacific coastal plain to the south and the Chiapas Depression to the north, or releasing it back into the atmosphere through evapotranspiration to fall again as rain.