At the confluence of two major rivers in the Caribbean lowlands of northern Costa Rica, La Selva comprises 1,600 hectares (3,900 acres) of tropical wet forests and disturbed lands. It averages 4 m (over 13 feet!) of rainfall that is spread rather evenly throughout the year.
La Selva is situated within tropical and premontane wet forest, with about 73% of its area as primary tropical rain forest.
La Selva was originally established in 1954 by Dr. Leslie Holdridge, as a farm dedicated to experimentation on mixed plantations for the improvement of natural resources management. It was purchased in 1968 by the Organization for Tropical Studies and declared a private biological reserve and station. Since then, it has become one of the most important sites in the world for research on tropical rain forest. Over 240 scientific papers are published yearly from research conducted at the site.