Official name: Commonwealth of Puerto Rico
Area: 9,104 square kilometers (3,515 square miles)
Highest point on mainland: Cerro de Punta (1,338 meters/4,390 feet)
Lowest point on land: Sea level
Hemispheres: Northern and Western
Time zone: 8 A.M. = noon GMT
Longest distances: 179 kilometers (111 miles) from east to west; 58 kilometers (36 miles) from north to south
Land boundaries: None
Coastline: 501 kilometers (313 miles)
Territorial sea limits: 22 kilometers (12 nautical miles)
Puerto Rico, a commonwealth of the United States of America, is located at the eastern end of the Greater Antilles archipelago, between the Atlantic Ocean and the Caribbean Sea. It is 1,609 kilometers (1,000 miles) southeast of the U.S. mainland, between the island of Hispaniola to the west and the Virgin Islands to the east. In addition to its main island, Puerto Rico also includes three smaller ones: Vieques and Culebra to the east and Mona to the west.
Puerto Rico has no territories or dependencies.
Trade winds from the northeast moderate Puerto Rico's tropical climate. Temperatures year-round generally stay between 21°C and 27°C (70°F and 80°F), although more extreme temperatures are possible in lower inland areas and on the southern coast. The mean temperature in San Juan is 24°C (75°F) in January and 27°C (81°F) in July. Hurricanes are a hazard between August and October. Average annual rainfall varies from 91 centimeters (36 inches) in the south, to 152 centimeters (60 inches) at San Juan, to as much as 457 centimeters (180 inches) in the mountains. Rainfall is distributed fairly evenly throughout the year.
Puerto Rico's main island, rectangular in shape, has a hilly and mountainous interior ringed by a narrow coastal plain. The major mountain system is the Cordillera Central, which bisects the western and central parts of the island.
Puerto Rico is bordered on the north by the rough, cold waters of the Atlantic Ocean and on the south by the warmer, calmer Caribbean Sea.
The waters just off the coast are shallow, but a few miles to the north the ocean floor drops to a depth of 1,829 meters (6,000 feet). Some 64 kilometers (40 miles) farther north lies the Puerto Rico Trench. At its western end is the Milwaukee Depth, where the ocean floor plunges more than 8,380 meters (27,493 feet)— among the deepest ocean trenches in the world, and the greatest known depth in the Atlantic.
Puerto Rico is separated from the island of Hispaniola to the west by the Mona Passage, and from the Virgin Islands to the east by both the Vieques Sound and the Virgin Passage.
Vieques, Puerto Rico's largest island aside from the main island, has an area of about 135 square kilometers (52 square miles), much of it occupied by a U.S. naval training facility. Culebra, which also lies to the east of the main island, is an archipelago consisting of a largely flat main island surrounded by twenty islets. Mona Island, to the west, has an area of 52 square kilometers (20 square miles).
Puerto Rico's coastline is moderately indented at most points. San Juan Bay is in the northeast, and Mayagüez Bay marks the western end of the island. Águila Point and Brea Point are in the southwest. The shore has both rocky and sandy beaches.
There are no natural lakes in Puerto Rico, but there are more than a dozen artificial ones.
The major rivers flow northward over the mountains to the coast. These waterways include the La Plata River (the longest), the Río Grande de Loíza (the widest), the Bayamón River, and the Río Grande de Arecibo. The rivers in the south are fewer, shorter, and smaller in volume.
There are no deserts in Puerto Rico.
Puerto Rico's steep mountains descend to foothills before giving way to the coastal plains that ring the island. They span 24 kilometers (15 miles) at their widest point, and the strip of plain on the north is only 8 kilometers (5 miles) wide. The Turabo Valley, a largely agricultural area, lies between three mountain chains in the eastern part of the island.
Steep mountain slopes cover nearly one-fourth of the island. The highest and longest mountain range is the Cordillera Central, which extends 97 kilometers (60 miles) across the center of the island and reaches elevations of over 914 meters (3,000 feet). Puerto Rico's highest peak, Cerro de Punta (1,338 meters/ 4,390 feet), is part of this system, which rises rapidly from the southern coast and ascends more gradually in the north. The other major mountain system is the Sierra de Luquillo in the east, where the country's most famous peak, El Yunque (1,062 meters /3,483 feet) is located. A third mountain range—the Sierra da Cayey—is found in the southeast.
The Camuy River cave system is home to a rare species of fish that is completely blind.
Numerous cliffs, caves, sinkholes, and tunnels have been carved by rainwater into the limestone of Puerto Rico's karst region in the northwest. The subterranean caves at the Camuy River form one of the largest cave systems in the world. The largest single cave, Cueva Clara, is 210 meters (695 feet) long.
Puerto Rico's karst region in the interior northwest of the island lies on a plateau ranging in elevation from 30 to 213 meters (100 to 700 feet).
Dams built on all but one of Puerto Rico's major rivers have created more than a dozen reservoirs. Lakes Guayabal, Guajataca, Dos Bocas, and La Plata are among the largest of these reservoirs.
Luxner, Larry. Puerto Rico. Boston: Houghton Mifflin, 1995.
Marino, John. Puerto Rico: Off the Beaten Path . Guilford, CT: Globe Pequot Press, 2000.
Pariser, Harry S. The Adventure Guide to Puerto Rico . Edison, NJ: Hunter Publications, 1996.