The El Triunfo Biosphere Reserve, decreed in 1990, is located in the Sierra Madre de Chiapas in the municipalities of Acacoyagua, Ángel Albino Corzo, Montecristo de Guerrero, La Concordia, Mapastepec, Pijijiapan, Siltepec and Villa Corzo near the Pacific Ocean with 119177 hectares .