Puerto Rico is a self-governing unincorporated territory of the United States located in the northeastern Caribbean, east of the Dominican Republic and west of the Virgin Islands.
It is composed of an archipelago that includes the main island of Puerto Rico and a number of smaller islands and keys, the largest of which are Vieques, Culebra, and Mona (Amoná).
Puerto Rico has an area of 5,325 square miles (13,790 km2). The maximum length from east to west is 110 miles (180 km), and the maximum width from north to south is 40 miles (64 km).
The main island is mostly mountainous with large coastal areas in the north and south. The main mountain range is called “La Cordillera Central” (The Central Range), visible in the center of the island. An algal bloom can be seen off the northeastern coast.
Puerto Rico has 17 lakes, all man-made, and more than 50 rivers, most originating in the Cordillera Central. Rivers in the northern region of the island are typically longer and of higher water flow rates than those of the south, since the south receives less rain than the central and northern regions.