Established in 1978, the park was formed as an agreement with environmental lobbyists to limit and prevent development of the area after the construction of the Limon Highway, a major road linking the capital to the Caribbean cargo port of Puerto Limón.

The park was named after former Costa Rican president Braulio Carrillo, whose administration had helped foster the nation's early agricultural economy and had built the first road linking San José to the Caribbean coast.

The park also protects areas of the Sarapiquí River watershed, including large amounts of primary cloud and rainforest, and the flora and fauna that makes it their home.

Both the large size (108,970 acres) of Braulio Carrillo National Park, and its varied altitude of 3,000 metres (9,800 ft) between the highest and lowest points, make it home to several WWF ecoregions.

[1] Ranging from high-altitude cloud forests to lowlands tropical rainforest, it has one of the highest levels of biodiversity in Costa Rica.