This is not a botanical garden but a working research facility of the U.S. Department of Agriculture. It's located on Rte. 65, between Post Street and Rte. 108, adjacent to the University of Puerto Rico Mayagüez campus and across the street from the Parque de los Próceres (Patriots' Park). At the administration office, ask for a free map of the tropical gardens, which have one of the largest collections of tropical plant species intended for practical use, including cacao, fruit trees, spices, timbers, and ornamentals. There are lots of trees and a wide variety of plants. A hacienda-style building houses the visitor's office. The area is divided into fruit trees, a palm plantation, a bamboo forest, and a botanical garden. There are labs, greenhouses, and other research facilities throughout the area.