Also known as the San Ramón Biological Reserve, this protected area is located on the Atlantic side of the Tilarán Cordillera and its administration is the responsibility of the Western H.Q. of the University of Costa Rica. It has an altitude range from 800 to 1,500 m and rainfall is about 3,500 mm per year. The area is mountainous with steep slopes. Some of the rivers flowing across it have formed deep canyons, and it mainly consists of flows of basalt, andesitic lava, agglomerates and tufas, and autoclastic breccias.
The vegetation, typical of premontane cloud forest and lower montane forests, is a mixture of species belonging to low and high areas and, besides the arboreal vegetation up to 40 m, contains a great many palms, ferns, begonias, heliconias, lianas, bromeliads, mosses and orchids. Two outstanding species are the passion flower (Passiflora tica), a tree with attractive white flowers, and the ramonean heliconia (Heliconia ramonensis), a plant of the undergrowth with striking vivid red inflorescenses. Thanks to the presence of dense vegetations – 90% is primary forest – abrupt topography and high precipitation, the area has great hydroelectric potential.