Mexico

1 LOCATION AND SIZE

Mexico is the northernmost—and by far the largest—country on the isthmus that connects North and South America. It is considered part of North America, while the much smaller countries to its south make up Central America. Extending southeastward from its border with the United States, Mexico forms a generally narrowing cone, broken in the northwest by the long, narrow peninsula of Baja California and in the extreme southeast by the blunt peninsula of the Yucatán. With a total area of 1,972,550 square kilometers (761,602 square miles), Mexico is almost three times as large as the state of Texas.

2 TERRITORIES AND DEPENDENCIES

Mexico has no territories or dependencies.

3 CLIMATE

About half of Mexico lies to the south of the Tropic of Cancer. Due to altitude and other geographical factors, however, temperatures in the north can exceed those in the south.

The various temperature zones in most of Mexico are generally categorized by altitude rather than latitude. Areas at elevations up to 914 meters (3,000 feet)—the coastal lowlands and the Yucatán peninsula—are terra caliente ("hot land") and have a tropical climate. The plateau (914 to 1,829 meters/3,000 to 6,000 feet) is terra templada ("temperate land"), with a moderate climate, and the mountains (1,829 meters/6,000 feet) are terra fria ("cold land"). The average annual temperatures for cities in these three regions are, respectively, Veracruz (25°C/77°F), Jalapa (19°C/66°F), and Pachuca (15°C/59°F).

In the south, temperatures between seasons vary by as few as 5°C (10°F); temperature extremes are much greater in the north, however. For example, Baja California and the Sonoran Desert can record summer highs of 43°C (110°F) and winter lows of 0°C (32°F). Rainfall varies greatly by region, ranging from under 25 centimeters (10 inches) per year in Baja California to 500 centimeters (200 inches) in the rainforests of Tabasco. The north generally gets less rainfall than the south, but the entire gulf coastal plain is a wet area.

4 TOPOGRAPHIC REGIONS

Mexico can be divided into five major regions: 1) the Pacific Northwest, which includes the northwestern mainland plus the Baja California peninsula; 2) the large Central Plateau, which extends down the center of the country and includes the Sierra Madre; 3) the lowlands of the Gulf Coast and the Yucatán Peninsula; 4) Central Mexico, which occupies the transverse volcanic range at the southern end of the Central Plateau; and 5) the highlands south of Central Mexico.

5 OCEANS AND SEAS

Most of Mexico's eastern coast borders the Gulf of Mexico, but the eastern shore of the Yucatán Peninsula borders the Caribbean Sea. The western coast of the mainland and the eastern coast of the Baja California peninsula border the Gulf of California, an inlet of the Pacific Ocean. The western coast of Baja California borders the Pacific.

Seacoast and Undersea Features

The waters of the Pacific off the western coast of the Baja peninsula are known for the array of marine life they harbor, and are especially famous as the only place in the world where the gray whale calves. The southeastern shore of the Baja peninsula is the location of the world's northernmost coral reef.

Sea Inlets and Straits

The Yucatán Channel, between the northeast tip of the Yucatán Peninsula and southern Cuba, divides the Caribbean Sea from the Gulf of Mexico. The narrow Isthmus of Tehuantepec that connects the Mexican mainland to the Yucatán Peninsula and Central America is bordered by two gulfs, the Bahia de Campeche (to the north) in the Gulf of Mexico, and the much smaller Gulf of Tehuantepec (to the south) in the Pacific Ocean.

Islands and Archipelagos

Mexico has several islands, both off the western coast of the Baja California peninsula, dotting the Gulf of California to the east. It also has a few islands opposite the southern end of the western coastal plain (in the state of Nayarit), and several more near the northeastern tip of the Yucatán Peninsula, including the islands of Cozumel and Mujeres.

Coastal Features

Mexico's coastline includes sandy beaches, which draw visitors to coastal resort areas like Acapulco and Cancún (known for its white-sand beaches), but in parts of Baja California and along the southern Pacific coastline, the mountains come right down to the sea. Other parts of the coast are bordered with mangrove-lined lagoons.

Mexico's three Pacific coastlines—both coasts of the Baja California peninsula and the western coast of the mainland—are heavily indented in the north, with multiple bays and inlets. The shoreline in the southern reaches of the mainland coastal plain and the southern part of Baja California's western coast are much smoother. The coast is still smooth but becomes slightly uneven as it curves around the southern highlands, and then becomes almost perfectly smooth at the Gulf of Tehuantepec. The northernmost section of Mexico's gulf coast is the site of a distinctive inland waterway called the Laguna Madre, one of only three coastal lagoons in the world that are hypersaline (saltier than the ocean). There is a nearly identical lagoon—also called the Laguna Madre—just north of the U.S. border along the Texas gulf coast. A short distance south of Mexico's Laguna Madre is another good-sized lagoon area called the Laguna de Tamiahua.

6 INLAND LAKES

Mexico has only a few natural lakes. Lake Chapala on the outskirts of Guadalajara is the country's largest natural lake. It is approximately 75 kilometers (50 miles) long and has a maximum width of around 20 kilometers (13 miles). Another relatively large lake in Central Mexico is Lake Cuitzeo.

7 RIVERS AND WATERFALLS

Few major rivers traverse Mexico. The longest is the Rio Grande (known in Mexico as the Río Bravo del Norte). It flows southeast for some 2,092 kilometers (1,300 miles) before draining into the Gulf of Mexico, and the river forms more than half of Mexico's border with the United States. Its tributary, the Conchos, drains a large part of the Mesa del Norte. The Moctezuma-Panuco River flows eastward through the Sierra Madre Oriental into the Gulf of Mexico, draining the eastern part of the Mesa Central. Farther south, two larger rivers flow into the Gulf: the Papaloapan River, whose mouth is near Veracruz, and the Grijalva-Usumacinta River, which flows through the Chiapas Highlands. The Lerma River rises in the volcanic highlands, near Mexico City, then flows westward to Lake Chapala. Flowing westward farther south is the Balsas River.

8 DESERTS

Much of the area north of the Tropic of Cancer is considered tropical desert or steppe land. The semiarid Balsas Depression south of the transverse volcanic highlands also has a desert environment.

9 FLAT AND ROLLING TERRAIN

The northern section of the Central Plateau (the Mesa del Norte) includes extensive flat areas, but it is broken by numerous hill ranges, most of them longitudinal. Central Mexico's terrain includes rolling hills in addition to its volcanic peaks and basins.

10 MOUNTAINS AND VOLCANOES

Two-thirds of Mexico is mountainous. The massive Sierra Madre Occidental that forms the western edge of the Central Plateau is the country's most extensive mountain system and an extension of the Sierra Nevada range in the United States. Its peaks average 2,438 to 2,743 meters (8,000 to 9,000 feet) in elevation. At the eastern edge of the Central Plateau, the shale and limestone peaks of the Sierra Madre Oriental range, rising to maximum heights of over 3,658 meters (12,000 feet), form an extension of the Rocky Mountain range.

The loftiest peaks of the volcanic fracture zone at the southern edge of the Central Plateau extend laterally from the Pacific Ocean almost to the Gulf of Mexico. These mountains are known by various names, including the Cordillera Neovolcanica, the Sierra Volcanica Transversal, and the Transverse Volcanic Range. Most of the country's highest peaks are in this chain. The range is anchored on the east, not far from the Gulf of Mexico, by the volcanic cone of Orizaba, the country's highest mountain, at an elevation of 5,700 meters (18,702 feet). South of the fracture zone lies the Sierra Madre del Sur range with altitudes of up to 3,048 meters (10,000 feet). This range is not related to the mountain systems of northern Mexico.

Beyond the Isthmus of Tehuantepec, the Sierra Madre de Chiapas extend to the Guatemalan border, separated from the Pacific by a fairly broad coastal plain. The remaining major mountain system, the Chiapas Highlands, occupies most of the interior east of the Isthmus of Tehuantepec and south of the Yucatán Peninsula.

11 CANYONS AND CAVES

The Sierra Madre Occidental range has a number of steep canyons called barrancas. The most dramatic of these is the Barranca del Cobre; it is the Mexican counterpart to the Grand Canyon in the United States.

12 PLATEAUS AND MONOLITHS

Mexico's large Central Plateau extends southward down the center of the country from the U.S. border to the Isthmus of Tehuantepec, narrowing somewhat from north to south. Average elevations range from 1,219 meters (4,000 feet) in the north to over 2,438 meters (8,000 feet) in the south. At approximately its midpoint, near the city of San Luis Potosi, the plateau is interrupted by a series of ranges that cross between the two Sierra Madre systems. The drier, low-lying part of the plateau north of this point is called the Mesa del Norte. To the south lies the Mesa Central, which is higher, wetter, and flatter.

13 MAN-MADE FEATURES

Rivers that have been dammed for irrigation purposes include the Yaqui, the Fuerte, and the Culiacán Rivers, all of which flow through the narrow Pacific coastal plain. The Morelos Dam on the Colorado River at the head of the Gulf of California has converted the desert land of the Mexicali Valley into an important agricultural area devoted primarily to cotton farming. The Balsas River provides hydroelectric power through a dam at the Sierra Madre del Sur.

14 FURTHER READING

Books

Butler, Ron. Dancing Alone in Mexico: From the Border to Baja and Beyond . Tucson: University of Arizona Press, 2000.

Tree, Isabella. Sliced Iguana: Travels in Unknown Mexico . London: Hamish Hamilton, 2001.

Wauer, Roland H. Naturalist's Mexico . College Station: Texas A&M University Press, 1992.

Web Sites

Mexico Travel Guide. http://www.go2mexico.com/ (accessed April 24, 2003).

UpTravel.com . http://www.1uptravel.com/geography/mexico.html (accessed April 24, 2003).