Panama

Relief

Panama is bounded to the north by the Caribbean Sea (an extension of the Atlantic Ocean) and to the south by the Pacific Ocean. It has an elongated S shape, with its Caribbean coastline stretching some 800 miles (1,290 km) and the Pacific coast some 1,060 miles (1,700 km); however, a line drawn from the Costa Rican frontier in the west to the Colombian border in the east would extend only 480 miles (770 km). The shortest distance across the isthmus is about 30 miles (50 km), from the mouth of the Nergalá (Necategua) River, which flows into the Gulf of San Blas on the Caribbean shore, to the mouth of the Chepo River on the Pacific coast. Nearly as narrow is the portion of the isthmus traversed by the Panama Canal.

Britannica Quiz

The Country Quiz

A central spine of mountain ranges extends almost the entire length of Panama, dividing the country into Atlantic- and Pacific-facing slopes. The two principal ranges, the Tabasará Mountains (Cordillera Central) in the west and the Cordillera de San Blas in the east, are separated near the center of the country by a saddle of lower land. This depression (the Panama Canal site) divides the country again—roughly into western and eastern halves. Of the four quadrants thus formed, the southwestern has the largest number of settlements; however, the environs of the canal account for most of Panama’s population and commerce. The country’s highest peak is an inactive volcano, Barú (Chiriquí), which reaches an elevation of 11,401 feet (3,475 meters).

Paralleling the principal mountain chains, a lower mountain arc extends along Panama’s southern coast. It appears only in well-separated segments—for example, on Azuero Peninsula as the Canajagua Massif and in eastern Panama as the Sierra de Jungurudó, Sapo Mountains, and the Majé Mountains. The highlands and mountains are made up primarily of igneous (volcanic) rocks.

Explore Britannica Premium!

The trusted destination for professionals, college students, and lifelong learners.

SUBSCRIBE

The lowlands include the plains of Panamá and Chiriquí provinces, the plains and hills of Colón province, the Chepo and Chucunaque river basins in the east, and the narrow northeastern plains of the Caribbean region. Sedimentary rocks such as slates and shales underlie most of the lowland zones.

The Pacific coastline is extended by the Azuero Peninsula and the Gulf of Panama and by numerous headlands and bays, whereas the largest embayment on the Caribbean side is Chiriquí Lagoon. The Pacific coastline is more indented and irregular, and its continental shelf is much wider than that on the Atlantic side. In addition, most of the republic’s more than 1,600 islands lie off its Pacific coast; they include the Perlas Archipelago (Pearl Islands) and the islands of Taboga, Cébaco, Parida, Jicarón, and Coiba, the largest. The principal archipelagoes off the Caribbean coast are those of Bocas del Toro and San Blas.

Drainage and soils

Of Panama’s many short rivers, those that flow to the Caribbean include the Sixaola, Changuinola, Indio, Cricamola, La Miel, and Chagres. Rivers flowing to the Pacific include the Chiriquí Viejo, Santa María, Chepo, Chucunaque, and Tuira. During the rainy season the Tuira is navigable for some 40 miles (60 km) and the Chepo for 20 miles (30 km). Water in the Panama Canal does not flow from coast to coast; rather, it is released from the rain-fed Gatún and Alajuela (Madden) lakes in the central highlands. In effect, the water flows to both coasts simultaneously via the canal’s system of locks and dams. For details on the engineering and operation of the waterway, see Panama Canal.

Soils are commonly reddish to brown and rich in clay. They vary in fertility, and in many areas crops can be grown continuously only if fertilizers are applied. On poorer soils, a shifting subsistence agriculture is practiced. Under this system small plots are cleared, cropped for a few years, then abandoned until their natural fertility is restored—a practice called roza in Panama.

Areas of alluvial soils (which develop from clay, silt, sand, and gravel deposited by streams) are especially fertile but are limited to the lower parts of river valleys. The commercial banana plantations around Puerto Armuelles and in western Bocas del Toro province are mainly on alluvial soils. Some of the soils along the inland edges of coastal mangrove swamps have also proved productive. In some areas, exceptionally fertile soils have developed from volcanic ash.