Mexico has 31 states plus Mexico City, giving 32 federative entities (entidades federativas) in the United Mexican States. Each state is officially a “free and sovereign state” with its own constitution, governor and congress. Mexico City is not a state, but since 29 January 2016 it has been a federal entity with comparable powers and, since 2017, its own constitution. The largest state is Chihuahua, at about 247,413 km², and the smallest is Tlaxcala, at about 3,997 km². The State of Mexico, which wraps around the capital, is the most populous, with 16,992,418 people at the 2020 census. Below these 32 entities sit 2,462 municipalities and the 16 boroughs of Mexico City. The present map took 150 years to settle: the first constitution of 1824 created 19 states, and the last two territories became states only in 1974.
The 1824 Constitution: 19 states, four territories and a Federal District
When the short-lived Mexican Empire fell and the federal republic was proclaimed in 1823, the old Spanish provinces turned themselves into states. The State of Mexico and Guanajuato were first, accepted on 20 December 1823, followed within days by Oaxaca, Puebla, Michoacán, San Luis Potosí, Veracruz, Yucatán, Jalisco, Zacatecas and Querétaro. Yucatán came in on 23 December 1823 as the “Federated Republic of Yucatán”, covering what are now Yucatán, Campeche and Quintana Roo.
Article 5 of the Federal Constitution of 4 October 1824 then fixed the founding map. It listed 19 states: Chiapas, Chihuahua, Coahuila and Texas, Durango, Guanajuato, México, Michoacán, Nuevo León, Oaxaca, Puebla, Querétaro, San Luis Potosí, Sonora and Sinaloa, Tabasco, Tamaulipas, Veracruz, Xalisco (Jalisco), Yucatán and Zacatecas. It added four territories, Alta California, Baja California, Colima and Santa Fe de Nuevo México, and left the status of Tlaxcala to a later law. Two of those states were double units. Coahuila and Texas was one state, and Sonora and Sinaloa formed the Estado de Occidente. Chiapas, a former part of the Captaincy General of Guatemala, joined on 14 September 1824, the only state whose admission was decided by its own people in a referendum.
The capital needed a home outside any state. Congress debated moving it to Querétaro, but on 30 October 1824 it voted 52 to 31 to keep Mexico City and create a Federal District. The district, made official on 18 November 1824, covered about 220 km² centred on the Zócalo. Losing the city forced the State of Mexico to move its government to Texcoco.
The first split followed quickly. On 14 October 1830 Sinaloa was separated from the Estado de Occidente, leaving Sonora on its own and bringing the count to 20 states.
Centralism, Texas and the 1848 cession
The federal map was suspended for most of the next decade. A law of 3 October 1835 introduced centralism, and the Seven Constitutional Laws of 30 December 1836 replaced the states with 24 departments whose governors were chosen by the president. Under that scheme Coahuila and Texas were treated separately, Colima was folded into Michoacán, Tlaxcala into México, and the Federal District was abolished.
The reaction redrew the edges of the country. Zacatecas rose against centralism in 1835, and as punishment part of its territory was turned into the Aguascalientes Territory. Texas broke away in 1836 and became an independent republic. Coahuila, Nuevo León and Tamaulipas proclaimed a Republic of the Rio Grande on 17 January 1840, which collapsed by 6 November that year. Yucatán declared independence in 1841 and stayed out until 1848, and Tabasco seceded from 13 February 1841 to 2 December 1842.
The federal constitution of 1824 was restored on 22 August 1846, in the middle of the war with the United States. That war ended with the Treaty of Guadalupe Hidalgo, signed on 2 February 1848, under which Mexico ceded 55% of its territory, including present-day California, Nevada, Utah, most of Arizona and parts of New Mexico, Colorado and Wyoming, and accepted the Rio Grande as the boundary of Texas, for $15 million. The territories of Alta California and Nuevo México disappeared from the Mexican map. The Gadsden Purchase, which took effect on 8 June 1854, removed a further 76,800 km² from Chihuahua and Sonora and fixed the line that our guide to the US–Mexico border follows today.
Guerrero, Campeche, Hidalgo and Morelos: new states from 1849 to 1869
With the north settled, the changes moved to the centre and south. Guerrero was created on 27 October 1849 from parts of the State of Mexico, Puebla and Michoacán. In 1853 Antonio López de Santa Anna, back in power and governing through departments again, created three short-lived territories: Tehuantepec (29 May 1853), Isla del Carmen (16 October 1853) and Sierra Gorda (1 December 1853). He also enlarged the Federal District almost eightfold in 1854, from about 220 km² to 1,700 km², to protect the mountain passes south of the capital.
The Constitution of 1857 swept those territories away and returned to a federation of states. Tlaxcala and Colima, former territories, became states in 1856, and Aguascalientes, the piece cut from Zacatecas, followed on 5 February 1857. Campeche was separated from Yucatán and admitted on 29 April 1863. Finally, the State of Mexico lost two more large slices in 1869: Hidalgo (16 January) and Morelos (17 April). Emperor Maximilian’s 1865 plan to divide the country into at least 50 departments, drawn up by the geographer Manuel Orozco y Berra, did not outlast the fall of his empire in 1867. By 1869 Mexico had 27 states, and the borders of central Mexico were essentially the ones on today’s map.
From Tepic to Quintana Roo: the territories that became states, 1917–1974
The last four states began life as federal territories run from Mexico City. The Tepic Territory was created by President Manuel González on 12 December 1884 from land that had belonged to Jalisco since 1824. The Constitution of 1917, written at the end of the Revolution, turned it into the state of Nayarit, admitted in 1917.
Quintana Roo had a stormier start. Porfirio Díaz created the territory by decree in 1902, carving it out of Yucatán mainly so that the federal army could confront the Maya in the Caste War of Yucatán. It was handed back to Yucatán on 10 June 1913 by Venustiano Carranza, then re-established on 28 June 1915 after a revolt in Yucatán. It was abolished once more on 14 December 1931, when President Pascual Ortiz Rubio divided it between Yucatán and Campeche to save money, and restored on 11 January 1935 under Lázaro Cárdenas after residents protested.
Baja California went through two stages. In December 1930 Congress amended Article 43 of the Constitution to split the peninsula’s single territory at the 28th parallel into Baja California Norte and Baja California Sur. On 15 November 1951 President Miguel Alemán proposed making the northern territory a state, and Baja California was admitted on 16 January 1952 as the 29th. The final step came on 8 October 1974, when Quintana Roo and Baja California Sur were admitted on the same day as the 30th and 31st states, leaving Mexico with no territories at all.
Mexico City’s 2016 change from Distrito Federal to the 32nd entity
The one piece that still is not a state is the capital. The Federal District’s borders were last adjusted between 1898 and 1902, when its southern edge with Morelos was redrawn. In 1970 the district was organised into 16 boroughs (delegaciones), and a 1993 amendment to Article 44 of the Constitution declared Mexico City and the Federal District to be the same entity. Residents first elected their head of government and legislative assembly in 1997.
On 29 January 2016 the Federal District was abolished and renamed Ciudad de México, or CDMX, and the city became the 32nd federal entity. Its own constitution was ratified on 31 January 2017, and its 16 boroughs, now called alcaldías, are run by elected mayors. A clause in the federal constitution still prevents it from becoming a state while it remains the seat of the federal powers. Our guide to Mexico City, the capital of Mexico covers the city itself.
Chihuahua to Tlaxcala: how the 32 entities compare today
The result of all this redrawing is a federation of very uneven parts. In the north, the largest states are the ones that lost land to the United States: Chihuahua (247,413 km²), Sonora (179,355 km²) and Coahuila (151,595 km²). Chihuahua alone is about 12.5% of Mexico’s 1,972,550 km², and its capital, Chihuahua city, is smaller than its border city of Ciudad Juárez. In Baja California, too, the capital Mexicali is outgrown by Tijuana, and in Quintana Roo, Chetumal is outgrown by Cancún.
The smallest states are those cut from the old core around the capital: Tlaxcala (3,997 km²), Morelos (4,879 km²) and Aguascalientes (5,616 km²). Mexico City covers only about 1,494 km² but had 9,209,944 residents in 2020, making it the second most populous entity after the State of Mexico. Jalisco (8,348,151) and Veracruz (8,062,579) come next, while Colima (731,391) and Baja California Sur (798,447) are the least populous. Mexico’s 2,462 municipalities are just as unevenly spread: Oaxaca has 570 of them, Baja California Sur only 5.
A few state names still carry the history. The State of Mexico grew out of the colonial Intendancy of Mexico, and both it and the country take their name from Mēxihco, the Nahuatl name of the Mexica island city in Lake Texcoco where Tenochtitlan and Tlatelolco stood; the deeper origin of the word is debated, as our article on why Mexico is called Mexico explains. Hidalgo and Morelos honour independence leaders, Quintana Roo is named for the patriot Andrés Quintana Roo, and several states keep a hero in their official names, such as Coahuila de Zaragoza and Veracruz de Ignacio de la Llave.