Coahuila in the context of "Prairie dogs"

Texas (/ˈtɛksəs/ TEK-səss) is the most populous state in the South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the west, and an international border with the Mexican states of Chihuahua, Coahuila, Nuevo León, and Tamaulipas to the south and southwest. Texas has a coastline on the Gulf of Mexico to the southeast. Covering 268,596 square miles (695,660 km) and with over 31 million residents as of 2024, it is the second-largest U.S. state by both area and population. Texas is nicknamed the "Lone Star State" for the single star on its flag, symbolic of its former status as an independent country, the Republic of Texas.

Spain was the first European country to claim and control Texas. Following a short-lived colony controlled by France, Mexico controlled the land until 1836 when Texas won its independence, becoming the Republic of Texas. In 1845, Texas joined the United States of America as the 28th state. The state's annexation set off a chain of events that led to the Mexican–American War in 1846. Following victory by the United States, Texas remained a slave state until the American Civil War, when it declared its secession from the Union in early 1861 before officially joining the Confederate States on March 2. After the Civil War and the restoration of its representation in the federal government, Texas entered a long period of economic stagnation.

The international boundary separating Mexico and United States extends from the Pacific Ocean to the Gulf of Mexico. The border traverses a variety of terrains, ranging from urban areas to deserts. It is the most frequently crossed border in the world, with approximately 350 million documented crossings annually. Illegal crossing of the border to enter the United States has caused the Mexico–United States border crisis. It is one of two international borders that the United States has, the other being the northern Canada–United States border; Mexico has two other borders: with Belize and with Guatemala.

Four American Sun Belt states border Mexico: California, Arizona, New Mexico and Texas. One definition of Northern Mexico includes only the six Mexican states that border the U.S.: Baja California, Chihuahua, Coahuila, Nuevo León, Sonora and Tamaulipas. The total length of the continental border is 3,145 kilometers (1,954 miles). From the Gulf of Mexico, it follows the course of the Rio Grande (Río Bravo del Norte) to the border crossing at Ciudad Juárez, Chihuahua, and El Paso, Texas. Westward from El Paso–Juárez, it crosses vast tracts of the Chihuahuan and Sonoran deserts to the Colorado River Delta and San Diego–Tijuana, before reaching the Pacific Ocean.

Chihuahua, officially the Free and Sovereign State of Chihuahua, is one of the 31 states which, along with Mexico City, are the 32 federal entities of Mexico. It is located in the northwestern part of Mexico and is bordered by the states of Sonora to the west, Sinaloa to the southwest, Durango to the south, and Coahuila to the east. To the north and northeast, it shares an extensive border with the U.S. adjacent to the U.S. states of New Mexico and Texas. The state was named after its capital city, Chihuahua City; the largest city is Ciudad Juárez. In 1864 the city of Chihuahua was declared capital of Mexico by Benito Juárez during the Reform War and French intervention until 1867. The city of Parral was the largest producer of silver in the world in 1640. During the Mexican War of Independence, Miguel Hidalgo was executed on July 30, 1811, in Chihuahua city.

Although Chihuahua is primarily identified with its namesake, the Chihuahuan Desert, it has more forests than any other state in Mexico, aside from Durango. Due to its varied climate, the state has a large variety of fauna and flora. The state is mostly characterized by rugged mountainous terrain and wide river valleys. The Sierra Madre Occidental mountain range, part of the continental spine that also includes the Rocky Mountains, dominates the state's terrain, and is home to the state's greatest attraction, Las Barrancas del Cobre, or Copper Canyon, a canyon system larger and deeper than the Grand Canyon. The state also has the largest crystal cave in Mexico known as the Naica cave discovered in 2001. Chihuahua is also home to the archaeological site of Paquimé in Casas Grandes that was created by the people of the Mogollon culture of Northern Mexico and is recognized as an UNESCO World Heritage site. Chihuahua is the largest state in Mexico by area, with an area of 247,455 square kilometres (95,543 sq mi), it is slightly larger than the United Kingdom, and slightly smaller than Wyoming, the tenth largest US state by area. The state is consequently known under the nickname El Estado Grande ('The Great State' or 'The Big State').

The Rio Grande (/ˌriːoʊ ˈɡrænd/ or /ˌriːoʊ ˈɡrɑːndeɪ/) in the United States or the Río Bravo (del Norte) in Mexico (Spanish pronunciation: [ˈri.o ˈβɾaβo ðel ˈnoɾte]), also known as Tó Ba'áadi in Navajo, is one of the principal rivers (along with the Colorado River) in the Southwestern United States and in northern Mexico. The length of the Rio Grande is 1,896 miles (3,051 km), making it the 4th longest river in the United States and in North America by main stem. It originates in south-central Colorado, in the United States, and flows to the Gulf of Mexico. The Rio Grande drainage basin (watershed) has an area of 182,200 square miles (472,000 km); however, the endorheic basins that are adjacent to and within the greater drainage basin of the Rio Grande increase the total drainage-basin area to 336,000 square miles (870,000 km).

The Rio Grande with its fertile valley, along with its tributaries, is a vital water source for seven U.S. and Mexican states, and flows primarily through arid and semi-arid lands. After traversing the length of New Mexico, the Rio Grande becomes the Mexico–United States border, between the U.S. state of Texas and the northern Mexican states of Chihuahua and Coahuila, Nuevo León and Tamaulipas; a short segment of the Rio Grande is a partial state-boundary between the U.S. states of New Mexico and Texas. Since the mid–twentieth century, only 20 percent of the Rio Grande's water reaches the Gulf of Mexico, because of the voluminous consumption of water required to irrigate farmland (e.g. the Mesilla and Lower Rio Grande Valleys) and to continually hydrate cities (e.g. Albuquerque); such water usages are additional to the reservoirs of water retained with diversion dams. 260 miles (418 km) of the river in New Mexico and Texas are designated as the Rio Grande Wild and Scenic River.

José Santiago Vidaurri Valdez (July 24, 1809 – July 8, 1867) was a controversial and powerful governor of the northern Mexican states of Nuevo León and Coahuila between 1855 and 1864. He was an advocate of federalism.

In 1855, he supported the liberal Revolution of Ayutla, which overthrew the dictatorship of Antonio López de Santa Anna, the military strongman who dominated Mexican politics in the 1830s until his overthrow in 1855. Vidaurri stood by the liberal president Benito Juárez during the subsequent War of the Reform, a bloody civil war following Mexican conservatives' repudiation of the liberal government and the Constitution of 1857. During the war, Vidaurri commanded the liberal armies of the north. During the American Civil War (1861–65), Southern slave states had seceded from the United States and formed the Confederate States of America. Vidaurri sought advantageous trade relationships with the CSA, which bordered northern Mexico.

Zacatecas, officially the Free and Sovereign State of Zacatecas, is one of the 31 states of Mexico. It is divided into 58 municipalities and its capital city is Zacatecas.

It is located in north-central Mexico and is bordered by the states of Durango to the northwest, Coahuila to the north, Nayarit to the west, San Luis Potosí and Nuevo León to the east, and Jalisco, Guanajuato and Aguascalientes to the south. The state is best known for its rich deposits of silver and other minerals, its colonial architecture and its importance during the Mexican Revolution. Its main economic activities are mining, agriculture and tourism.

Nuevo León, officially the Free and Sovereign State of Nuevo León, is a state in northeastern Mexico. The state borders the Mexican states of Tamaulipas, Coahuila, Zacatecas, and San Luis Potosi, and has an extremely narrow international border with the U.S. state of Texas. Covering 64,156 square kilometers (24,771 square miles) and with a population of 5.78 million people, Nuevo León is the thirteenth-largest federal entity by area and the seventh-most populous as of 2020.

Monterrey, the state's capital, is the most populous city in Nuevo León and the ninth-largest in Mexico. Monterrey is part of the Monterrey metropolitan area, the second-largest metropolitan area in the country with an estimated population of 5.3 million people in 2020. About 92% of the state's population lives in the metropolitan area.

Northern Mexico (Spanish: el Norte de México, pronounced [el ˈnoɾte ðe ˈmexiko] ), commonly referred as The North (Spanish: El Norte), is an informal term for the northern cultural and geographical area in Mexico. Depending on the source, it contains some or all of the states of Baja California, Baja California Sur, Chihuahua, Coahuila, Durango, Nuevo León, Sinaloa, Sonora and Tamaulipas.

There is no specific border that separates the northern states from the southern states in Mexico. For some authors, only states that have a border with the United States are considered as northern Mexico, i.e. Baja California, Chihuahua, Coahuila, Nuevo León, Sonora and Tamaulipas. Others also include Durango, Sinaloa and Baja California Sur. Other people consider that the north starts above the Tropic of Cancer, but this description would include some parts of Zacatecas and San Luis Potosí that are not considered northern states.

The Chihuahuan Desert (Spanish: Desierto de Chihuahua, Desierto Chihuahuense) is a desert ecoregion designation covering parts of northern Mexico and the southwestern United States. It occupies much of far West Texas, the middle to lower Rio Grande Valley and the lower Pecos Valley in New Mexico, and a portion of southeastern Arizona, as well as the central and northern portions of the Mexican Plateau. It is bordered on the west by the Sonoran Desert, the Colorado Plateau, and the extensive Sierra Madre Occidental range, along with northwestern lowlands of the Sierra Madre Oriental range. Its largest, continual expanse is located in Mexico, covering a large portion of the state of Chihuahua, along with portions of Coahuila, north-eastern Durango, the extreme northern part of Zacatecas, and small western portions of Nuevo León. With an area of about 501,896 km (193,783 sq mi), it is the largest hot desert in North America. The desert is fairly young, existing for only 8,000 years.