Puerto Rico, a territory of the United States, is the easternmost island of the Greater Antilles in the Caribbean Sea and its geography describes an archipelago located between the Caribbean Sea and the North Atlantic Ocean, east of the Dominican Republic and west of the Virgin Islands. The main island of Puerto Rico is the smallest and most eastern of the Greater Antilles. With an area of 3,515 square miles (9,104 km²), it is the third largest island in the United States and the 82nd largest island in the world. In addition, two small islands, Culebra and Vieques lie off the east coast, and the tiny island of Mona to the west. Puerto Rico is divided into three geographical areas:
Central Interior Mountain Ranges: This area covers most of the island of Puerto Rico. The mountainous core is formed by the Cordillera Central and the Sierra de Luquillo, continuations of the Cordillera Central on neighboring Hispaniola. This area includes the interior mountains, hills, mountain sides, and low areas within the mountains. These mountain ranges are La Cordillera Central, La Sierra de Cayey, La Sierra de Luquillo, and La Sierra Bermeja. The highest peak is the 4,398 feet Cerro La Punta.
Northern Karst: is a region of limestone hills shaped like haystacks. It covers an area in the north of the Island from the center to the western end. This area is a plateau with elevations from 100-700 ft. The northern part is made up of limestone hills while the interior is pocketed with hills, holes and caves. Many caves here have not been completely explored.
Coastal Plains: The largest cities on the island are located here, San Juan, Ponce and Mayaguez. Beaches and sand dunes are abundant on Puerto Rico's 1,126 kilometers of coast. There are many small rivers the largest of which are Río de la Plata, Río Grande de Loíza, Rí Grande de Manatí, and Río Grande de Arecibo. Over 300 miles of coast rim the island shaded by coconut palms.