Caimito is one of the 18 barrios of the municipality of San Juan, Puerto Rico located in the mountainous part of the municipality. With a land area of , Caimito is the second largest barrio in the municipality of San Juan, Puerto Rico. In 2010 it had 21,825 inhabitants and a population density of 4,034.2 per sq.mi. Located in the southern part of San Juan, Caimito is bordered by barrios Tortugo and Quebrada Arenas to the west, by Monacillo to the north, by Cupey to the east and by the municipality of Caguas to the south.
The name Caimito comes from the Caimito tree, which is common in the region. The word caimito is possibly a Spanish adaptation (-ito being the Spanish diminutive) of the Taino word caima, possibly related to the Carib acayouman, meaning crocodile (see caiman).
Assigned as a suburb of Río Piedras in 1835 by Pedro Tomás de Córdova, who was Captain General of Puerto Rico from 1816 to 1836, Caimito consisted of 3,595.30 acres or land or roughly 5.16 squa