墨西哥介绍

as well as a judiciary, and its citizens elect by direct voting, a governor (gobernador) for a six-year term, as well as representatives (diputados locales) to their respective state congresses, for three-year terms. The 31 states and the Federal District are collectively called "federal entities", and all are equally represented in the Congress of the Union.

Mexican states are also divided into municipalities (municipios), the smallest official political entity in the country, governed by a mayor or "municipal president" (presidente municipal),elected by its residents by plurality.

Municipalities can be further

subdivided into

non-autonomous boroughs or

in semi-autonomous auxiliary

presidencies.

Constitutionally, Mexico City, as the capital of the federation and seat of the powers of the Union, is the Federal District, a special political division in

Mexico that belongs to the

federation as a whole and not to a

particular state, and as such, has

more limited local rule than the nation's states. Nonetheless, since 1987 it has progressively gained a greater degree of autonomy, and residents now elect a head of government (Jefe de Gobierno) and representatives of a Legislative Assembly directly. Unlike the states, the Federal District does not have a constitution but a statute of government. Mexico City is conterminous and coextensive with the Federal District.

Situated in southern North America at about 23° N and 102° W, Mexico comprises much of Middle America. Physiographically, the lands east of the Isthmus of Tehuantepec including the Yucatán Peninsula (which together comprise around 12% of the

country's area) lie within Central

America; geologically, the

Trans-Mexican Volcanic Belt

delimits the region on the north.

Geopolitically, however, Mexico

is commonly considered a North American country.

Mexico's total area is 1,972,550 km², making it the world's 14th largest country by total area, and includes approximately 6,000 km² of islands in the Pacific Ocean (including the remote Guadalupe Island and the Islas Revillagigedo), Gulf of Mexico, Caribbean Sea, and Gulf of California. On its north, Mexico shares a 3,141 km border with the United States. The meandering Río Bravo del Norte (known as the Rio Grande in the United States) defines the border from Ciudad Juárez east to the Gulf o f Mexico. A series of natural and artificial markers delineate the United States-Mexican border west from Ciudad Juárez to the Pacific Ocean. On its south, Mexico shares an 871 km border with Guatemala and a 251 km border with Belize.

Mexico is crossed from north to south by two mountain ranges known as Sierra Madre Oriental and Sierra Madre Occidental,which are the extension of the

Rocky Mountains from

northern North America. From

east to west at the center, the

country is crossed by the

Trans-Mexican Volcanic Belt also known as the Sierra Nevada. A fourth mountain range, the Sierra Madre del Sur, runs from Michoacán to Oaxaca. As such, the majority of the Mexican