Mexico City

Mexico City serves as both the capital and largest city of Mexico, and it holds the title of North America's most populous urban center. Recognized as an Alpha world city in the 2024 Globalization and World Cities Research Network ranking, it stands among the globe's key cultural and financial hubs. The city lies in the Valley of Mexico on the high Mexican Central Plateau, at an elevation of 2,240 meters (7,350 feet). Its administrative structure includes 16 boroughs, known as alcaldías, which are further split into neighborhoods called colonias.

According to the 2020 census, the city proper had 9,209,944 residents within a land area of 1,495 km², making it Mexico's primate city and the second-largest Spanish-speaking city proper worldwide, after Lima. The broader Greater Mexico City area, as defined by federal and state governments, counted 21,804,515 people, ranking as the world's 15th-largest metropolitan area and the second-largest urban agglomeration in the Western Hemisphere, behind São Paulo. In 2011, Greater Mexico City's GDP reached $411 billion, placing it among the world's most productive urban areas. The city alone contributed 15.8% of Mexico's GDP, while the metropolitan area accounted for roughly 22%. If it were an independent nation in 2013, Mexico City would have been Latin America's fifth-largest economy.

As the Americas' oldest capital, Mexico City is one of only two founded by Indigenous peoples. It originated as Tenochtitlan, a Mexica city established around 1325 on islands within Lake Texcoco. Following the 1521 siege of Tenochtitlan, the city was largely destroyed and then reconstructed following Spanish urban designs. The municipality of Mexico City was created in 1524, and from 1585 onward it was officially known by its current name. During the Spanish colonial era, the city served as a major political, administrative, and financial center. After Mexico gained independence, the surrounding territory was organized in 1824 as the country's new and only federal district (the DF).

Following years of demands for greater political autonomy, residents earned the right in 1997 to elect both the head of government and members of the unicameral Legislative Assembly. Since then, left-wing parties—first the Party of the Democratic Revolution and later Morena—have held both offices. The city has enacted several progressive policies, including legalized abortion, a limited form of euthanasia, no-fault divorce, same-sex marriage, and legal gender change. On 29 January 2016, the Federal District was officially renamed Ciudad de México, or CDMX. These reforms granted the city more autonomy and altered aspects of its government and political structure, though a constitutional clause still prevents it from becoming a state while it remains Mexico's capital.

Up until 2013, the city was commonly referred to by the initialism "DF" (from Distrito Federal). Since 2013, the abbreviation "CDMX" has become more widespread. Colloquially, the city is simply called "México" in local geographic contexts, a usage also seen on road signs and highway names. The informal demonym for residents is chilango, historically used pejoratively by outsiders to "connote a loud, arrogant, ill-mannered, loutish person." In turn, those living in Mexico City sometimes insultingly refer to people elsewhere as living in la provincia ('the provinces'), and many proudly embrace the term chilango. Formally, residents are called capitalinos (referring to the city being the capital), but "[p]erhaps because capitalino is the more polite, specific, and correct word, it is almost never utilized."

Mexico City was traditionally known as La Ciudad de los Palacios ("the City of Palaces"), a nickname attributed to Baron Alexander von Humboldt. During his 19th-century visit, he wrote a letter to Germany stating that Mexico City could rival any major European city. English politician Charles Latrobe also referenced it, writing: "... look at their works: the moles, aqueducts, churches, roads—and the luxurious City of Palaces which has risen from the clay-built ruins of Tenochtitlan..." in The Rambler in Mexico.

During the colonial period, the city's motto was "Muy Noble e Insigne, Muy Leal e Imperial" (Very Noble and Distinguished, Very Loyal and Imperial). Under Andrés Manuel López Obrador's administration (2018–24), a political slogan—la Ciudad de la Esperanza (the City of Hope)—was introduced. It quickly became a nickname but faded after the administration of Marcelo Ebrard adopted the motto Capital en Movimiento ("Capital in Movement"), which is not really treated as a nickname.

The oldest signs of human occupation in the area are those of the "Peñón woman" and others found in San Bartolo Atepehuacan (Gustavo A. Madero), originally believed to date to the lower Cenolithic period (9500–7000 BC). However, a 2003 study placed the Peñón woman's age at 12,700 years (calendar age), making her one of the oldest human remains discovered in the Americas. Analysis of her mitochondrial DNA suggests she was of Asian, European, or Aboriginal Australian origin.

The area was the destination of Teochichimeca migrations during the 8th and 13th centuries, peoples who gave rise to the Toltec and Mexica (Aztec) cultures. The Mexica arrived around the 14th century, settling first on the lake's shores. The city of Mexico-Tenochtitlan was founded by the Mexica in 1325 or 1327, built on an island in the center of the Valley of Mexico's inland lake system, shared with the smaller city-state of Tlatelolco.