Puerto Rico is the easternmost island of the Greater Antilles. It is bounded by the Atlantic Ocean on the north and the Caribbean Sea on the south. Mona Passage separates Puerto Rico from the Dominican Republic (on the island of Hispaniola) to the west; the Vieques Passage separates it from its island of Vieques to the east. Puerto Rico is located 1,600 km (1,000 mi) southeast of Florida, and about 965 km (600 mi) north of Caracas, Venezuela. The Virgin Islands lie about 65 km (40 mi) to the east (see Virgin Islands of the United States; British Virgin Islands).
The total area of Puerto Rico, including its three largest offshore islands, is 9,085 sq km (3,508 sq mi). The main island is shaped like a rectangle, with a 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).
Hills and steep mountains cover three-fourths of Puerto Rico. A narrow coastal plain and some inland valleys provide the only low-lying terrain. The central mountain chain is the Cordillera Central, which extends east and west and divides the island into its northern and southern regions. Other mountain ranges include Sierra de Luquillo in the northeast, Sierra de Cayey in the southeast, and Sierra Bermeja in the southwest. The highest point on the island is Cerro de Punta (1,338 m/4,390 ft) in the central part of the island. The most famous peak is El Yunque (Spanish for “the Anvil”), which rises 1,066 m (3,496 ft) above sea level in the Sierra de Luquillo. El Yunque is part of the Caribbean National Forest, and it has a tropical rain forest, which is a favorite tourist attraction. The coastal plain, which rings the mountains, is about 16 km (10 mi) wide in the north and about 13 km (8 mi) wide along the southern coast.
Puerto Rico possesses several offshore islands, the largest of which are Vieques, Culebra, and Mona. Vieques, which lies to the east, is the largest (population, 2000, 9,106). Its only urban center is Isabel Segunda. North of Vieques is the smaller island of Culebra (1,868). Its main town is Dewey. The U.S. Fish and Wildlife Service protects much of the island as a natural preserve. The third island, Mona, lies to the southwest in the Mona Passage. Much smaller than Vieques or Culebra, Mona Island is uninhabited and is known for its marine life.