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Geography of Puerto Rico

The island of Puerto Rico is a very popular tourist destination because of its location, rich history and warm atmostphere. The island is located in the Caribbean, between the Caribbean Se and the North Atlantic Ocean, east of the Dominican Republic, about 1,000 miles (1,600 km) southeast of Miami, Florida.

Puerto Rico is almost rectangular in shape, approximately 100 miles long by 35 miles wide and is the smallest and the most eastern island of the Greater Antilles (Cuba, Hispaniola, Jamaica and Puerto Rico). It consists of the main island of Puerto Rico and several smalller islands and keys, including Vieques, Culebra, Culebrita, Palomino (known by some by the Spanish Virgin Islands), Mona, and Monito.

Its coasts measures approximately 580 km, and if the adjacent islands Vieques and Culebra are included the coast measures approximately 700 km. With an area of 3,425 square miles (9,104 sq km), Puerto Rico is the third largest island in the United States and the 82nd largest island in the world.

Geographic Coordinates: Latitude: 18° 15" N   Longitude: 66° 30" W


Total Area: 9,104 sq km (3,508 sq mi)
The maximum length from east to west (from Punta Puerca to Punta Higuero) of 180 km (110 mi) and with a maximum width from north to south (from Isabella to Punta Colón) of 65 km (40 mi).

Land Area: 8,959 sq km
Comparative area: approximately three times the size of Rhode Island.

Water Area: 145 sq km

Region: North America

Subregion: Caribbean

Map References: Central America and the Caribbean

Map of Puerto Rico
Source: National Geographic Society

Interesting Fact
Puerto Rico is close to the deepest submarine depression in the North Atlantic Ocean. The Puerto Rico Trench, roughly parallel to the northern coast of the island of Puerto Rico and lying about 75 miles (120 km) to the north. The Puerto Rico Trench is about 1,090 miles (1,750 km) long and 60 miles (100 km) wide. The deepest point in the Atlantic Ocean, the Milwaukee Depth, lies within the Puerto Rico Trench, at a depth of 27,493 feet (8,380 meters) in the western end of the trench, about 100 miles (160 km) northwest of Puerto Rico. The origin of the trench can be traced back to the beginning of the Tertiary period. The Puerto Rico Trench appears to be part of a complex system of sinistral strike-slip faults in the north Caribbean; the trench seems to have been opened continuously for about 70 million years. It is partially filled with sediments.

The Caribbean's greatest known depth is Cayman Trench (Bartlett Deep) between Cuba and Jamaica, at approximately 25,216 feet (7,686 meters) below sea level.

To the west by Haití and the Dominican Republic (La Hispañola), separated by the Mona Passage ("Mona Canal"), to the east by the Virgin Islands, to the north by the Atlantic Ocean, and to the south by the Caribbean Sea.

Land boundaries: 0 km

Coastline: 501 km

Puerto Rico is under the U.S. customs jurisdiction. Borders are open between P.R. and the U.S., allowing for free movement of people and merchandise.

Maritime Claims:
Continental shelf: 200 NM (depth)
Exclusive economic zone: 200 NM
Territorial sea: 12 NM


Puerto Rico is composed of Jurassic to Eocene volcanic and plutonic rocks, which are overlain by younger Oligocene to recent carbonates and other sedimentary rocks. Most of the caverns and karst topography on the island occurs in the northern Oligocene to recent carbonates. The oldest rocks are approximately 190 million years old (Jurassic) and are located at Sierra Bermeja in the southwest part of the island.

Puerto Rico lies at the boundary between the Caribbean and North American plates. This means that it is currently being deformed by the tectonic stresses caused by the interaction of these plates.

Interesting Fact
70.8% of the world's surface is water, 29.2% is land.

Deep oceans waters fringe Puerto Rico. To the west, the Mona Passage, which separates the island from Hispaniola to the west, is about 80 miles (130 km) wide and more that 3,300 feet (1,000 meters) deep. Off the northern coast in the Atlantic Ocean at the boundary between the Caribbean and North American plates is the Puerto Rico Trench, the largest and deepest trench in the Atlantic. The trench is 800 kilometres (497 mi) long and has a maximum depth of 8,000 metres (26,247 ft) at Milwaukee Deep, which is the deepest point in the Atlantic Ocean. To the south the sea bottom descends to the 16,400 feet (5,000 meters) deep Venezuelan Basin of the Caribbean.

Because of the proximity to the two tectonic plates Puerto Rico experiences an average of five earthquakes (including aftershocks) with a magnitude greater than 1.5 occurring near per day.

Although the vast majority of these earthquakes are too small to be felt by people, but provides evidence that the North American plate is moving westward relative to the Caribbean plate at about two centimeters per year.


The territory is very mountainous (covering about 60%), except in the regional coasts, but Puerto Rico offers astonishing variety: rain forest, deserts, beaches, caves, oceans and rivers. Puerto Rico has three main physiographic regions: the mountainous interior, the coastal lowlands, and the karst area.

The mountainous interior is formed by a central mountain chain commonly known as the Cordillera Central, extending across the interior of the island, from Mayagüez to Aibonito, which transects the island from east to west. These mountain ranges are La Cordillera Central, La Sierra de Cayey, La Sierra de Luquillo, and La Sierra Bermeja.

The largest mountains are Cerro La Punta (1,338 m) in Jayuya; Rosas (1,267 m) found between Jayuya and Ciales, Guilarte (1,205 m) in Adjuntas, Tres Picachos (1,204 m) in Jayuya, and Maravilla (1,182m) in Ponce. Toward to the northeast is Sierra de Luquillo, whose highest peaks are: Toro Hill (1,074 m) found between Río Grande, Naguabo and Las Piedras, and El Yunque Peak (1,065 m) found in Río Grande. Another mountain chain is the Sierra de Luquillo in the northeast.

The second main physiographic feature is the coastal lowlands, which extend 13 to 19 km (8 to 12 mi) inward in the north and 3 to 13 km (2 to 8 mi) in the south. A series of smaller valleys lie perpendicular near the west and east coast. This area was originally formed by the erosion of the interior mountains.

The third important physiographic feature is the karst region in the north. This area consists of formations of rugged limestone dissolved by water throughout the geological ages. This limestone region is an extremely attractive zone of extensive mogotes or haystack hills, sinkholes, caves, limestone cliffs, and other karst features. The karst belt extends from Aguadilla, in the west, to a minor haystack hills formation in Loíza, just east of San Juan.

El Yunque Peak is the Caribbean National Forest. These 28,000 acres are all that remain of the rain forest that once covered much of the island (indeed, much of the entire northern Caribbean). More than 100 billion gallons (yes, billion) of rain fall here each year, creating a lush forest with plants of incredible proportions and variety. A moist hike or horseback ride take you past 240 species of trees, some thousands of years old, 50 species of ferns, 20 varieties of wild orchids and riotous multitude of flowers. Living in the forest (all over the island in fact but quite far to spot) is the tiny coquí frog. The name is derived from his cricket like ko-kee chirp, this tiny creature (a quarter to one inch in size) is considered to be the national mascot. Other forest areas are: Guajataca in the Northwest; Río Abajo, between Arecibo and Utuado; Aguirre in the South; Piñones, east of San Juan; Guánica, west of Ponce; Maricao, Guilarte, Toro Negro and Carite (Guavate), all on the transinsular Panoramic Route. The largest number of bird species can be found at Guánica Forest, which is home to 700 plant species of which 48 are endangered and 16 exist nowhere else. Guánica's dry forest vegetation is unique and the Forest has been declared an International Biosphere Reserve by UNESCO.

Puerto Rico also has some of the most important caves in the west hemisphere. The Río Camuy runs underground for part of its course, forming the third largest subterranean river in the world. There are fine examples of stalactites, stalagmites and, of course, plenty of bats. Located near to Lares, on Route 129, Km 9.8, guided tours available, open Wed to Sun, US$10 for adults, U$S7 for children. Close by you can find the Cueva del Infierno, on which 2,000 caves have been discovered; in them live 13 species of bat, the coquí, crickets, an arachnid called the "guavá", and other species. Guide tours available, for details contact (787) 898-2723.

Interesting Fact
The islands of Cayo Diablo, St. Thomas, St. John, Tortola, Guana, Greater Camanoe, Necker Cay, and Virgin Gorda were once known as the Puerto Rico Bank.

Another unique environment can be found on Mona Island, 50 miles off the west coast of Puerto Rico. Like the Galapagos Islands, this untouched island has species which are not found elsewhere. Mona is a protected island, under the management of the United States National Park Service and the Puerto Rican Natural Resources Department. Accessible by a sometimes difficult, long boat ride, the island is available for sport diving to those who make special arrangements and are willing to rough it out.


Different classification schemes exist for the soils of Puerto Rico. One physiographic approach, based on a scientific classification by the U.S. Soil Conservation Service, can be summarized into five general soil types: humid coastal plains, semiarid coastal plains, humid uplands, semiarid uplands, and humid upland valleys. Another classification by soil scientists at the University of Puerto Rico groups the island's soils into coastal lowlands, alluvium, coastal plains, alluvium in terraces, upland dark, and upland reddish-purple. Traditionally, tropical soils have been looked upon as infertile and unproductive and of poor agricultural value. However, tropical countries provide such high biomass products as sugar cane, bananas, coffee, and tobacco.

Rivers and Lakes

Puerto Rico, due to its relatively short width and its east-west running mountain chain, does not have long rivers or large lakes. The longest river is the Grande de Arecibo, which flows to the northern coast. Other rivers include La Plata, Cibuco, Loíza, and, Bayamón all draining to the north, and the Grande de Añasco, draining to the west. There are other perennial rivers, mostly draining to the north and west. Many of the rivers draining south run dry most of the year; nonetheless, with heavy rainfall, they can cause flooding.

Puerto Rico does not have natural lakes, although it has 15 reservoirs, commonly called lakes, formed by damming the main rivers to produce hydroelectric power and water for irrigation. Hydroelectricity accounts for less than 1% of the electricity generated, as most electric power uses petroleum as the energy source. The island has such natural lagoons as the Condado and San Jose in San Juan, Piñones and Torrecillas in Carolina, Joyuda in Cabo Rojo, and Laguna Tortuguero in Manatí.

Flora and Fauna

Several thousand varieties of tropical plants grow in Puerto Rico, including the kapok tree ("Ceiba") with its thick trunk, the poinciana (a prickly tropical shrub with brilliant reddish blossoms), the breadfruit, and the coconut palm. A tropical rain forest in the northeastern section of the island has tree ferns, orchids, and mahogany trees; part of this tropical area is included in the Caribbean National Forest. In the dry southwestern corner of Puerto Rico are cactus and bunch grass. Puerto Rico has no large wild mammals. The mongoose was brought in to control rats on sugar cane plantations. Iguanas and many small lizards abound, and bats are present. The island has few animals native to the island, found almost nowhere else in the world, the coquí (mentioned above) and the Puerto Rican Parrot (Amazona vittata) ("cotorra puertorriqueña") lives only in a few hidden areas of the Caribbean National Forest. The Puerto Rican Parrot is bright green, about a foot in length, with red forehead, blue primary wing feathers, and flesh-colored bill and feet. Barracuda, kingfish, mullet, Spanish mackerel, tuna, lobster, and oysters are among the many fish inhabiting coastal waters.




Highest Point: Cerro Punta, 1,338 m (4,389 ft)

Lowest Point: Sea level, Caribbean Sea 0 m

Natural Resources
Some stone, fish, copper and nickel, potential for on-shore and off-shore crude oil.

Land Use:
arable land: 6.76%
permanent crops: 4.51%
other: 88.73% (2011)

Irrigated Land: 220 sq km (10.67 %) (2012)

Natural Hazards: periodic droughts; hurricanes

Environment Current Issues: erosion; occasional drought has caused water levels in reservoirs to drop and has prompted water rationing.

Many small rivers and high central mountains ensure land is well watered; south coast relatively dry; fertile coastal plain belt in north.

Note: important location along the Mona Passage - a key shipping lane to the Panama Canal; San Juan is one of the biggest and best natural harbors in the Caribbean.


Of the 1,200 bodies of water Puerto Rico only classifies 50 of them rivers. Numerous rivers flow down from the mountains to distinct coastal plains. The Central Range divides the north (Atlantic) and south (Caribbean) watersheds. The northern rivers are long, rich and tranquil waters in comparison to the southern rivers, and the coast is wet and green. The major rivers are: Grande de Loíza (65 km), Bayamón (40 km), La Plata (80 km), and Grande de Arecibo (55 km). To the west and the east are the rivers basins which form the water systems and these rivers are: Culebrinas (45 km), Grande de Añasco (65 km), and Guanajibo (36 km). Subterranean streams are abundant, especially toward the northwest. Between the most important thermal fountain is "Los Baños de Coamo" found in Coamo. In the southwest, mangroves have created a unique canal system. Puerto Rican rivers are not navigable by large vessels, but they provide electrical power and irrigation.


The climate is Tropical Marine with an average temperature of 80°F (26°C). Puerto Rico enjoys warm and sunny days most of the year. Lightweight clothing is appropriate year-round. The winds, which blow from the East, moderate temperatures and rainfall. In the interior, the temperature fluctuates between 73°F and 78°F (22°C and 25°C). The temperature in the south is usually a few degrees higher than the north and temperatures in the central interior mountains are always cooler than the rest of the island.

Rainfall tends to be evenly distributed throughout the year, but doubles during the months from May to October, which, unfortunately, coincides with hurricane season, as falls from November to April, with a driest period from January to April. The north coast gets twice as much rain as the south coast. Annual precipitation in the north is 1,550mm (61.02 inches); in the south is 910mm (36 inches), in coastal regions 101-381 cm (40-150 inches) and in the mountains 508 cm (200 inches).

Puerto Rico is expose to the cyclones of Caribbean, although less than Jamaica, Cuba, and the Lesser Antilles. Hurricanes frequently occur between August and October, although the U.S. National Weather Service considers the hurricane season for the North Atlantic Basin to run from June 1 to November 30. The North Atlantic Basin includes the Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico. Hurricane seasons during 1995-2004 have averaged 13.6 tropical storms (34-63 knots), 7.8 hurricanes (>63 knots) and 3.8 major hurricanes (>95 knots).

Dozens of hurricanes have been recorded in the island's history, but probably the most destructive was San Ciriaco, which struck on August 8, 1899.

The relative humidity is high, about 80% throughout the year.

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Did You Know?

The oldest city in the United States is St. Augustine in Florida, that is according to a continuously settled Europeans in the city. But the United States jurisdiction recognises San Juan as the oldest city in the US territory of Puerto Rico.