It is located in the extreme southeast of Nicaragua between the municipalities of El Castillo, Río San Juan and Bluefields in the South Caribbean Coast; declared through Decree 527, published in the official gazette La Gaceta No. 78 on April 17, 1991.
It has an area of 316,720 hectares, made up of lagoons, rivers and estuaries, wetlands, coastal plains and mountain formations that ensure an excellent spectacle of nature. It presents characteristic vegetation of the tropical humid forest, highlighting species such as laurel, mahogany, royal cedar, santa maría, broom palm; as well as the mangrove forest represented by species such as the water stick or milk beard.
In this forest there are bird species of great national and regional importance such as the Harpy eagle, green limpet and bell bird, in addition to aquatic and marine birds of the Caribbean; likewise, flocks of migratory species abound, among them plovers, runners and boobies; Herons, seagulls, fregatas and pelicans are also abundant. The species widely distributed in the wooded area are reptiles such as the helmet chameleon, brown lizard, spanish chameleon; and amphibians like the frog poisonous black-green, frog red arrowhead, frog forest bright, rain frog and glass frog.