Braulio Carrillo National Park is located 20 kilometers northeast of San José. The part of Braulio Carrillo that most people see is the southern area on either side of the Siquirres Highway on the way to the Atlantic coast. If you're coming from San José, the road to Limon is marked as the Siquirres Highway. The park headquarters is located less than 1 kilometer before the Zurqui tunnel on the right side of the highway.

The park lies in one of the most rugged regions in the country. Almost the entire landscape is broken up by towering mountains heavily cloaked with thick forest and by innumerable swollen rivers that carve deep canyons often with sheer vertical walls. The terrain and the heavy rainfall (the park receives an average of about 4,500 mm. a year) conspire to create an infinite number of waterfalls that can be seen everywhere. The parkland includes two extinct volcanoes, Cacho Negro with an easily seen conical shape, and Barba which is composed of several craters. Two of these are Barba Lake which is a round lake of crystal-clear water that measures 70 meters in diameter, and Danta Lake which measures 500 meters in diameter. The Las Marías Peaks, which are easily seen from the city of San José, are the remains of a caldera like structure that existed there.

The plant life in the park is composed of very dense, complex evergreen forest. The kind of forest varies according to the variations that exist in the topography, watersheds, temperature, cloud cover and rainfall. The tallest forest and those with the largest number of species are located in the park lowlands. In the upper and more rugged reaches of the park, the trees are stunted and deformed and there are fewer species. Most of the park is covered with primary forest in which there are 6,000 plant species.

Here is an abundance of tree ferns, heliconias, palm trees and bromeliads. Poor man's umbrella is a plant frequently seen growing alongside the road. It can grow as high as 1.5 meters and is unmistakable because of the enormous size of its leaves.
Frogs and toads abound in the park, especially in the area known as Bajo de la Hondura. An endemic species is the Bufo holdridgei toad which is frequently seen on Barba Volcano and in the Bajos del Tigre region. The most venomous snake in the country, the bushmaster also lives in the park.

A modern highway, which has been named Braulio Carrillo, crosses the park from northeast to southwest. It has excellent look-out points from which views of the river canyons, volcano cones and waterfalls can be enjoyed.

Trees found here: mountain cypress, winter's bark tree, wild fig, olive, mayo, alcanfor, copal, crabwood, quaruba, banak, jiggerwood,

Some of the animals found here: howler monkey, spider monkey, white-faced capuchin monkey, tapir, jaguar, cougar, ocelot, paca, northern tamandua, red brocket, kinkajou, agouti, Mexican tree porcupine, two-toed sloth, and three-toed sloth.

Birds found here: resplendent quetzal, bare-necked umbrella bird, ornate hawk-eagle, solitary eagle, osprey, sooty robin, clay-colored robin, king vulture, guan, greater sunbittern, collared trogon, black-faced solitaire, and three-wattled bellbird, and other species 347 in total