Mexico City (Spanish: Ciudad de México, México, D.F., and occasionally México) is the capital and largest city in the country of Mexico. As the seat of the Powers of the Union (i.e. seat of the Mexican federal government), Mexico City is also the Federal District. It is the most important political, economic, cultural and financial center in the country and a global city in Latin America. Located in the Valley of Mexico, a large valley in the high plateaus at the center of Mexico, at an altitude of 2,240 metres (7,300 ft), the city consists of sixteen boroughs. Its 2009 estimated population exceeds 8.84 million people, and with a land area of 1,485 square kilometres (573 sq mi), Mexico City is the most densely populated city in the country.

According to the most recent definition agreed upon by the federal and state governments, the Mexico City metropolitan area's population is 21.2 million people, making it the largest metropolitan area in the Americas and the third largest agglomeration in the world. The entire metropolitan area had a Gross Domestic Product (GDP) of $390 billion USD in 2005, making Mexico City the 25th largest economy in the world, richer (as measured by the GDP of the entire metropolitan area) than industrialized countries such as Taiwan and developing countries like Iran. It is also ranked as the eighth richest city in the world. According estimates, as of 2008, the city proper, as opposed to the metropolitan area, had a nominal income per capita of $25,258 USD, above the national average ($10,321 USD), and on par with those of Portugal, which has a comparable population, and significantly above South Korea, and Czech Republic. However, according to the same estimates, the per capita income of the entire metropolitan area is slightly above US$11,000, essentially in line with that of the country.

The Flag of Mexico (Spanish: Bandera de México) is a vertical Tricolour of green, white, and red with the national coat of arms charged in the center of the white stripe. While the meaning of the colors has changed over time, these three colors were adopted by Mexico following independence from Spain during the country's War of Independence, and subsequent First Mexican Empire. The current flag was adopted in 1968, but the overall design has been used since 1821, when the First National Flag was created. The current law of national symbols, Law on the National Arms, Flag, and Anthem, that governs the use of the national flag has been in place since 1984.

At the time of the flag's adoption, the Italian tricolor was not in use: the flag now contains the coat of arms, in order to distinguish it from that of Italy. Red, white, and green are the colors of the national liberation army in Mexico. The central emblem is the Aztec pictogram for Tenochtitlan (now Mexico City), the center of their empire. It recalls the legend that inspired the Aztecs to settle on what was originally a lake-island. The form of the coat of arms was most recently revised in 1968. Aztec legend held that they should found their city on the spot where they saw an eagle on a nopal, eating a snake. Ribbon in the national colors are at the bottom of the coat of arms. Throughout history, the flag has changed four times, as the design of the coat of arms and the length-width ratios of the flag have been modified. However, the coat of arms has had the same features throughout: an eagle, holding a serpent in its talon, is perched on top of a prickly pear cactus; the cactus is situated on a rock that rises above a lake. The coat of arms is derived from an Aztec legend that their gods told them to build a city where they spot an eagle and a serpent, which is now Mexico City. The current national flag, the Fourth National Flag, is also used as the Mexican naval ensign by ships registered in Mexico.

The United Mexican States (Spanish: Estados Unidos Mexicanos ), commonly known as Mexico (/ˈmɛksɪkoʊ/) (Spanish: México [ˈmexiko]), is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of Mexico. Covering almost 2 million square kilometres (over 760,000 sq mi), Mexico is the fifth-largest country in the Americas by total area and the 14th largest independent nation in the world. With an estimated population of 111 million, it is the 11th most populous country and the most populous Hispanophone country on earth. Mexico is a federation comprising thirty-one states and a Federal District, the capital city.