Mexico–United States border facts for kids

Quick facts for kids Mexico–United States border
Characteristics
Entities	Mexico  United States
Length	3,145 kilometers (1,954 mi)
History
Current shape	April 18, 1972 Boundary Treaty of 1970
Treaties	Adams–Onís Treaty, Treaty of Limits, Treaty of Guadalupe Hidalgo, Gadsden Purchase

The vast majority of the current border was decided after the Mexican–American War (1846–1848). Most of the border is settled on the Rio Grande River on the border of Texas and northeastern Mexico. To the left lies San Diego, California and on the right is Tijuana, Baja California. The building in the foreground on the San Diego side is a sewage treatment plant built to clean the Tijuana River.

A typical plaque constructed by the International Boundary and Water Commission and mounted at the exact location of the border

The Mexico–United States border is an international border separating Mexico and the United States, extending from the Pacific Ocean in the west to the Gulf of Mexico in the east. The border traverses a variety of terrains, ranging from urban areas to deserts. The Mexico–U.S. border is the most frequently crossed border in the world with approximately 350 million documented crossings annually. It is the tenth-longest border between two countries in the world.

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.

Four American 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.

Geography

U.S. Border Patrol at Algodones Sand Dunes, California. The fence on the U.S.–Mexican border is a special construction of narrow, 4.6 m (15 ft) tall elements, that are movable vertically. This way, they can be lifted on top of the ever shifting sand dunes.

The Mexico–United States border extends 3,145 kilometers (1,954 miles), in addition to the maritime boundaries of 29 km (18 mi) into the Pacific Ocean and 19 km (12 mi) into the Gulf of Mexico.

The Mexico–U.S. border begins at the Initial Point of Boundary Between U.S. and Mexico, which is set one marine league (three nautical miles) south of the southernmost point of San Diego Bay. The border then proceeds for 227 km (141 mi) in a straight line towards the confluence of the Colorado River and Gila River. The border continues southwards along the Colorado River for 39 km (24 mi), until it reaches a point 32 km (20 mi) south of the Gila River confluence. The border then follows a series of lines and parallels totaling 859 km (534 mi). First, it follows a straight line from the Colorado River to the intersection of the 31° 20′ parallel north and the 111th meridian west. It then proceeds eastwards along the 31° 20′ parallel north up to a meridian 161 km (100 mi) west of the point where the Rio Grande crosses the 31° 47′ parallel north, It then proceeds northwards along that meridian up to the 31° 47′ parallel north and then eastwards along that parallel until it meets the Rio Grande.

According to the International Boundary and Water Commission, the continental border then follows the middle of the Rio Grande—according to the 1848 Treaty of Guadalupe Hidalgo between the two nations, "along the deepest channel" (also known as the thalweg)—a distance of 2,020 km (1,255 mi) to its mouth at the Gulf of Mexico. The Rio Grande frequently meanders along the Texas–Mexico border. As a result, the U.S. and Mexico have a treaty by which the Rio Grande is maintained as the border, with new cut-offs and islands being transferred to the other nation as necessary. The Boundary Treaty of 1970 between Mexico and the U.S. settled all outstanding boundary disputes and uncertainties related to the Rio Grande border.

The U.S. states along the border, from west to east, are California, Arizona, New Mexico, and Texas. The Mexican states along the border are Baja California, Sonora, Chihuahua, Coahuila, Nuevo León, and Tamaulipas. Among the U.S. states, Texas has the longest stretch of the border with Mexico, while California has the shortest. Among the states in Mexico, Chihuahua has the longest border with the U.S., while Nuevo León has the shortest. Along the border are 23 U.S. counties and 39 Mexican municipalities.

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  Border Patrol patrolling the Rio Grande in an airboat in Laredo, Texas

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  The start of the border fence in the state of New Mexico – just west of El Paso, Texas

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  U.S. Border Patrol helicopter along El Camino del Diablo, Arizona–Sonora border, 2004

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  Border between Nogales, Arizona, on the left, and Nogales, Sonora, on the right

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  On the left: Nogales, Arizona; on the right, Nogales, Sonora

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  Beach in Tijuana at the border in 2006

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  A CBP Border Patrol vehicle sitting near Mexico–U.S. border

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  View of Cross Border Xpress (CBX) bridge from parking lot on U.S. side, with Tijuana Airport on the left and the CBX U.S. terminal on the right

History

Prior to the Mexican–American War

Map of Mexico in 1842

In the mid-16th century, after the discovery of silver, settlers from various countries and backgrounds began to arrive in the area. This period of sparse settlement included colonizers from different backgrounds. The area was part of New Spain. In the early 19th century, the U.S. bought the lands known as the Louisiana Purchase from France and began to expand steadily westward.

After the 1803 Louisiana Purchase, the border between the U.S. and New Spain was not clearly defined. The border was established in the 1819 Adams–Onís Treaty between the U.S. and Spain, which specified a border in the vicinity of the western edge of the Mississippi River watershed. Mexico gained its independence from Spain, and the border was reaffirmed in the 1828 Treaty of Limits.

Mexico attempted to create a buffer zone at the border that would prevent possible invasion from the north. The Mexican government encouraged thousands of their own citizens to settle in the region that is now known as Texas and even offered inexpensive land to settlers from the U.S. in exchange for populating the area. The influx of people did not provide the defense that Mexico had hoped for and instead Texas declared its independence in 1836, which lasted until 1845 when the U.S. annexed it.

Establishment of current border

San Diego together with Tijuana creates the bi-national San Diego–Tijuana metropolitan area

The constant conflicts in the Texas region in the mid-19th century eventually led to the Mexican–American War, which began in 1846 and ended in 1848 with the Treaty of Guadalupe Hidalgo. In the terms of the peace treaty, Mexico lost more than 2,500,000 square kilometers (970,000 sq mi) of land, 55% of its territory, including all of what is today California, Arizona, New Mexico, Utah, Nevada and parts of what is Colorado, Wyoming, Kansas, and Oklahoma. In addition, all disputes over Texas and the disputed territory between Rio Grande and Rio Nueces were abandoned.

Five years later, the Gadsden Purchase completed the creation of the current U.S.–Mexico border. The purchase was initially to accommodate a planned railway right-of-way. These purchases left approximately 300,000 people living in the once disputed lands, many of whom were Mexican nationals. Following the establishment of the current border, several towns sprang up along this boundary, and many of the Mexican citizens were given free land in the northern regions of Mexico in exchange for returning and repopulating the area.

Later history

El Paso, Texas (left) and Ciudad Juárez, Chihuahua (right), taken on June 30, 2022, from the International Space Station with north oriented towards the bottom-left side. The Rio Grande appears as a thin line separating the two cities through the middle of the photograph. El Paso and Juarez make up the third largest U.S. international metroplex after Detroit–Windsor and San Diego–Tijuana.

The Treaty of Guadalupe Hidalgo and another treaty in 1884 were the agreements originally responsible for the settlement of the international border, both of which specified that the middle of the Rio Grande was the border, irrespective of any alterations in the channels or banks. The Rio Grande shifted south between 1852 and 1868, with the most radical shift in the river occurring after a flood in 1864. By 1873 the moving river-center border had cut off approximately 2.4 square kilometers (590 acres) of Mexican territory in the El Paso-Juarez area, in effect transferring the land to the U.S.. By a treaty negotiated in 1963, Mexico regained most of this land in what became known as the Chamizal dispute and transferred 1.07 km² (260 acres) in return to the U.S. Border treaties are jointly administered by the International Boundary and Water Commission (IBWC), which was established in 1889 to maintain the border, allocate river waters between the two nations, and provide for flood control and water sanitation. Once viewed as a model of international cooperation, in recent decades the IBWC has been heavily criticized as an institutional anachronism, by-passed by modern social, environmental and political issues. In particular, jurisdictional issues regarding water rights in the Rio Grande Valley have continued to cause tension between farmers along the border, according to Mexican political scientist Armand Peschard-Sverdrup.

The economic development of the border region on the Mexican side of the border depended largely on its proximity to the U.S., because of its remoteness from commercial centers in Mexico. During the years of Mexican President Porfirio Díaz, between 1876 and 1910, the border communities boomed because of close ties to the U.S. and the Mexican government's support for financial investments from the U.S. Railroads were built that connected the northern Mexican states more to the U.S. than to Mexico, and the population grew tremendously. The mining industry also developed, as did the U.S.'s control of it. By the early 20th century companies from the U.S. controlled 81% of the mining industry and had invested US$500 million in the Mexican economy overall, 25% of it in the border regions.

Vehicle barrier in the New Mexico desert, 2010

The U.S. Immigration Act of 1891 authorized the implementation of inspection stations at ports of entry along the Mexican and Canadian borders. The U.S. Immigration Act of 1917 required the passing of a literacy test and a head tax by Mexicans wanting to enter the U.S. legally; however, during World War I, when labor shortages grew, the provisions were temporarily suspended. The U.S. Immigration Act of 1924 established the U.S. Border Patrol.

The Mexican Revolution, caused at least partially by animosity toward foreign ownership of Mexican properties, began in 1910. The revolution increased the political instability in Mexico but did not significantly slow U.S. investment. It did reduce economic development within Mexico, however, and the border regions reflected this. As the infrastructure of communities on the U.S. side continued to improve, the Mexican side began to fall behind in the construction and maintenance of important transportation networks and systems necessary to municipal development.

Although the Mexican Revolution caused insecurity in Mexico, it also strained U.S.–Mexico relations. With the Mexican Revolution lasting for 10 years, ending in 1920, and World War I simultaneously occurring between 1914 and 1918, the division between the U.S. and Mexico began to polarize the two nations. Constant battles and raids along the border made both authorities nervous about borderland security. The Zimmerman Telegram, a diplomatic cable sent by Germany but intercepted and decrypted by British intelligence, was meant to bait Mexico into war with the U.S. in order to reconquer what was taken from them during the Mexican-American War. This inspired the U.S. Federal Bureau of Investigation to monitor suspicious activities and potential violence at the border. Within 10 years, frequent provocations caused border towns to transform into battlefields, which intensified transborder restrictions, brought federal soldiers to patrol the border, and caused the construction of fences and barriers between border towns. When the battles concluded, restrictions for crossing the border were relaxed and most soldiers were sent home; however, the fences remained as a physical reminder of the division between the two nations. As years passed, more fences and higher barriers were established as attentions focused on the boundary demarcation between the U.S. and Mexico.

The first international bridge was the Brownsville & Matamoros International Bridge built in 1910. The first barrier built by the U.S. was between 1909 and 1911 in California, the first barrier built by Mexico was likely in 1918; barriers were extended in the 1920s and 1940s.

The Banco Convention of 1905 between the U.S. and Mexico allowed, in the event of sudden changes in the course of the Rio Grande (as by flooding), for the border to be altered to follow the new course. The sudden changes often created bancos (land surrounded by bends in the river that became segregated from either country by a cutoff, often caused by rapid accretion or avulsion of the alluvial channel), especially in the lower Rio Grande Valley. When these bancos are created, the International Boundary and Water Commission investigates if land previously belonging to the U.S. or Mexico is to be considered on the other side of the border. In all cases of these adjustments along the Rio Grande under the 1905 convention, which occurred on 37 different dates from 1910 to 1976, the transferred land was small (ranging from one to 646 acres) and uninhabited.

The Rio Grande Rectification Treaty of 1933 straightened and stabilized the river boundary through the highly developed El Paso-Juárez valley. Numerous parcels of land were transferred between the two countries during the construction period, 1935–1938. At the end, each nation had ceded an equal area of land to the other.

The Boundary Treaty of 1970 transferred an area of Mexican territory to the U.S., near Presidio and Hidalgo, Texas, to build flood control channels. In exchange, the U.S. ceded other land to Mexico, including five parcels near Presidio, the Horcon Tract and Beaver Island near Roma, Texas. On November 24, 2009, the U.S. ceded 6 islands in the Rio Grande to Mexico. At the same time, Mexico ceded 3 islands and 2 bancos to the U.S. This transfer, which had been pending for 20 years, was the first application of Article III of the 1970 Boundary Treaty.

Border crossing checkpoints

Climbing the Mexico–United States barrier fence in Brownsville, Texas

The border separating Mexico and the U.S. is the most frequently crossed international boundary in the world, with approximately 350 million legal crossings taking place annually.

There are 48 U.S.–Mexico border crossings, with 330 ports of entry. At these points of entry, people trying to get into the U.S. are required to open their bags for inspection. Border crossings take place by roads, pedestrian walkways, railroads and ferries. From west to east, below is a list of the border city "twinnings"; cross-border municipalities connected by one or more legal border crossings.

Going into Mexico from El Paso, Texas, U.S.

The total population of the borderlands—defined as those counties and municipios lining the border on either side—stands at some 12 million people.

Tijuana-San Ysidro border

San Ysidro Port of Entry through vehicle

The San Ysidro Port of Entry is located between San Ysidro, California and Tijuana, Baja California. Approximately 50,000 vehicles and 25,000 pedestrians use this entry daily. In the U.S., I-5 crosses directly to Tijuana, and the highway's southern terminus is this crossing. In 2005, more than 17 million vehicles and 50 million people entered the U.S. through San Ysidro. Among those who enter the U.S. through San Ysidro are transfronterizos, American citizens who live in Mexico and attend school in the U.S.

It has influenced the every day lifestyle of people that live in these border towns. Along the coast of Baja California, there are neighborhoods of Americans living in Tijuana, Rosarito Beach, and Ensenada, whose residents commute to the U.S. daily to work. Additionally, many Mexicans also enter the U.S. to commute daily to work. In 1999, 7.6% of the labor force of Tijuana was employed in San Diego.

Entrance to Mexico from San Diego, California, United States of America

The average wait time to cross into the U.S. is approximately an hour. The thousands of vehicles that transit through the border every day is causing air pollution in San Ysidro and Tijuana. The emission of carbon monoxide (CO) and other vehicle related air contaminants have been linked to health complications such as cardiovascular disease, lung cancer, birth outcomes, premature death, obesity, asthma and other respiratory diseases. The high levels of traffic collusion and the extended wait times has affected the mental health, stress levels, and aggressive behavior of the people who cross frequently. The San Ysidro border is heavily policed, separated by three walls, border patrol agents and the U.S. Immigration and Customs Enforcement.

Tijuana is the next target for San Diegan developers because of its fast-growing economy, lower cost of living, cheap prices and proximity to San Diego. While this would benefit the tourist aspect of the city, it is damaging to low-income residents that will no longer be able to afford the cost of living in Tijuana. Tijuana is home to many deportees from the U.S., many who have lost everything and do not have an income to rely on and are now in a new city in which they have to quickly adapt in order to survive. San Diego developers would bring many benefits to Tijuana, but deportees and the poor run the risk of being impacted by the gentrification of Tijuana.

Western Hemisphere Travel Initiative

The San Ysidro border crossing between San Diego and Tijuana

In late 2006, the U.S. Department of Homeland Security (DHS) announced a rule regarding new identification requirements for U.S. citizens and international travelers entering the U.S. implemented on January 23, 2007. This final rule and first phase of the WHTI specifies nine forms of identification, one of which is required to enter the U.S. by air: a valid passport; a passport card; a state enhanced driver's license or state enhanced non-driver ID card (available in Michigan, New York, Vermont, and Washington) approved by the Secretary of Homeland Security; a trusted traveler program card (Global Entry, NEXUS, FAST, or SENTRI); an enhanced tribal identification card; a Native American Tribal Photo Identification Card; Form I-872 – American Indian Card; a valid Merchant Mariner Document when traveling in conjunction with official maritime business; or a valid U.S. military identification card when traveling on official orders.

In August 2015, Mexico began enforcing a rule that all foreign citizens that plan to stay in the country for more than seven days or are travelling on business will have to pay a 330 pesos ($21) fee and show their passport.

Veterinary inspections

Passport stamp upon arrival in Tijuana, Baja California land border crossing

When animals are imported from one country to another, there is the possibility that diseases and parasites can move with them. Thus, most countries impose animal health regulations on the import of animals. Most animals imported to the U.S. must be accompanied by import permits obtained in advance from the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) and/or health certification papers from the country of origin.

Veterinary inspections are often required, and are available only at designated ports; advance contact with port veterinarians is recommended. Animals crossing the U.S.–Mexico border may have a country of origin other than the country where they present for inspection. Such animals include those from the U.S. that cross to Mexico and return, and animals from other countries that travel overland through Mexico or the U.S. before crossing the border.

Thousands of cars sit from fifteen minutes to two hours waiting to cross the border.

APHIS imposes precautions to keep out several equine diseases, including glanders, dourine, equine infectious anemia, equine piroplasmosis, Venezuelan equine encephalitis, and contagious equine metritis. APHIS also checks horses to prevent the introduction of ticks and other parasites. In the Lower Rio Grande Valley, U.S. Department of Agriculture inspectors look for horses and livestock that stray across the border carrying ticks. These animals are often called wetstock, and the inspectors are referred to as tickriders.

Per APHIS, horses originating from Canada can enter the U.S. with a Canadian government veterinary health certificate and a negative test for EIA. Horses from Mexico must have a health certificate; pass negative tests for EIA, dourine, glanders, and EP at a USDA import center; and undergo precautionary treatments for external parasites at the port of entry. Horses from other Western Hemisphere countries must have the same tests as those from Mexico and, except for horses from Argentina, must be held in quarantine for at least seven days as a check for VEE.

APHIS imposes similar testing and certification requirements on horses from other parts of the world but without the quarantine for VEE. These horses are held in quarantine—usually three days—or until tests are completed. Because the disease equine piroplasmosis (equine babesiosis) is endemic in Mexico but not established in the U.S., transportation of horses from Mexico to the U.S. requires evaluation of horses for the presence of this disease. A leading exception to this rule is the special waiver obtained by riders participating in the Cabalgata Binacional Villista (see cavalcade).

Import from the U.S. to Mexico requires evidence within the prior 45 days of freedom from EIA, among other requirements.

Barrier

The U.S. government had plans in 2006, during the Bush administration, to erect a border fence along the Mexico–U.S. border. The controversial proposal included creating many individual fences. Almost 966 km (600 mi) of fence were constructed, with each of the individual fences composed of steel and concrete. In between these fences are infrared cameras and sensors, National Guard soldiers, and SWAT teams on alert, giving rise to the term "virtual fence". Construction on the fence began in 2006, with each mile costing the U.S. government about $2.8 million. In 2010, the initiative was terminated because of costs, after having completed 1,030 km (640 mi) of either barrier fence or vehicle barriers, that were either new or had been rebuilt over older, inferior fencing. The Boeing-built SBI-net systems of using radar, watchtowers, and sensors (without a fence or physical barrier) were scrapped for being over budget, full of glitches, and far behind schedule.

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  The U.S.–Mexico border fence near El Paso, Texas

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  Portion of border near Jacumba, California, in 2003

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  Portion of border near Jacumba, California, in 2009 with enhanced security

Trump administration

U.S. Border Patrol agents review documents of individuals suspected of attempted illegal entry in 2019.

In 2016, Republican nominee for president Donald Trump proposed building a border wall to control immigration. He declared that, as president, he would force Mexico to pay all costs. On January 25, 2017, several days after his inauguration and two days in advance of a planned meeting in Washington, D.C., with Mexican President Enrique Peña Nieto, new U.S. president Trump signed Executive Order 13767 to enable the building of the wall. Peña Nieto denied that Mexico would pay for the wall and declined the meeting. Shortly after, Trump announced that he intended to impose a 20% tariff on Mexican goods. Mexico did not make any payments.

On September 20, 2017, California Attorney General Xavier Becerra filed a lawsuit alleging that the Trump administration has overstepped its powers in expediting construction of a border wall. As of the end of 2017, Mexico had not agreed to pay any amount toward the wall, no new tariffs on Mexican goods had been considered by the U.S. Congress, the U.S. Congress had not appropriated funding for a wall, and no further wall construction had started beyond what was already planned during the Obama administration.

In June 2018, the Trump administration established a new policy of separating parents from their children at the Mexican border. People asking for asylum at official ports of entry were "being turned away and told there's no room for them now." The U.S. and Mexico mutually placed tariffs on each other's exports.

Nogales border fence

On November 8, 2018, the Trump administration announced new rules to deny asylum to anyone who crosses into the U.S. illegally from any nation, at Trump's discretion. This was based on the Supreme Court decision of Trump v. Hawaii and the presidential powers of the Immigration and Nationality Act of 1965. Trump signed a proclamation the next day to specify that people crossing the Mexican border illegally would not qualify for asylum; he called the march of migrants from Central America towards the U.S. a "crisis". Civil rights groups strongly criticized the move, and several groups, including the Southern Poverty Law Center, the American Civil Liberties Union, and the Center for Constitutional Rights, filed a lawsuit in the U.S. District Court for the Northern District of California to challenge the proclamation. Judge Jon S. Tigar ruled in favor of the advocacy groups on November 20, 2018, placing an injunction on the administration to delay implementation of the rule. The administration appealed to the Ninth Circuit, where a divided 2-1 panel ruled that the new asylum rules were inconsistent with existing law and upheld the injunction. On December 21, 2018, the Supreme Court declined to hear the administration's challenge, leaving the injunction in place and preventing the asylum ban from being enforced.

During the 2018 fiscal year, U.S. border agents arrested 107,212 people traveling in families, a record-high number. During the following five months (October 2018 through February 2019), that record was shattered by the arrest of 136,150 people traveling in families. On March 31, 2019, Trump threatened to close the border, cutting off trade between the countries.

Proposed wall

U.S.–Mexico border wall, Progreso Lakes, Texas

While running for president, Trump estimated that a border wall would cost $8 to $12 billion and that he could force Mexico to pay for it. Cost estimates of the proposed wall vary widely. In early 2017, shortly after Trump took office, the DHS estimated the cost at $22 billion, while Democratic staff on the Senate Homeland Security and Governmental Affairs Committee estimated $70 billion to build the wall and $150 million in annual maintenance. Significant cost overruns and missed deadlines are common in government projects; in recent U.S. history, see, for example, the Big Dig and the Boeing Dreamliner.

In the summer of 2017, four major construction companies planned to bid for the contract. The Customs and Border Protection agency budgeted $20 million to hire these companies to build half-million-dollar prototypes of the wall. At this time, Congress had only approved $341 million to maintain the existing wall; no funds had been allocated to build new sections of wall. The DHS recommended that the wall's height should be between 18 and 30 feet (5.5 and 9.1 metres) and its depth should be up to 6 ft (1.8 m) to deter illegal immigrants from building tunnels.

During the Trump administration, 732 km (455 mi) were added to barrier between the two countries. The construction of the wall has been halted by President Joe Biden as he canceled the national emergency declaration, originally used by Trump.

Biden administration

The U.S. Border Patrol detained more than 1.7 million migrants crossing the U.S.-Mexico border illegally in fiscal year 2021, the highest number ever recorded. A greater demographic diversity of southwest border apprehensions have been noted in 2021.

On February 8, 2024, a group of 24 House Republicans wrote a letter to urge President Biden not to federalize the Texas National Guard in the midst of Texas wanting to crack down on the spike of illegal immigration on the U.S.-Mexico border.

Humanitarian assistance along the border

A volunteer from the Humane Border group is refilling water stations located on the desert of the U.S.-Mexico border.

Humanitarian groups such as Humane Borders, No More Deaths, and Samaritans provide water in order to reduce deaths of immigrants who are journeying through the Arizona desert. A policy passed in 2010 by the U.S. Fish and Wildlife federal agency allows water drums to be placed on roads of disturbed areas.

Mexicans crossing the Río Grande face the Big Bend National Park

Border zone policies

Per the La Paz Agreement, the official "border area" extends 100 km (62 mi) "on either side of the inland and maritime boundaries" from the Gulf of Mexico west into the Pacific Ocean. There is also a 100-mile border zone.

100-mile border zone

Members of the North Carolina Army National Guard monitoring the U.S.–Mexico border in southwest Arizona

The U.S. has established a 161 km (100 mi) border zone which applies to all U.S. external borders including all coasts, in effect covering two-thirds of the U.S. population, including a majority of the largest cities in the U.S. and several entire states (namely Connecticut, Delaware, Florida, Hawaii, Maine, Michigan, New Hampshire, New Jersey, and Rhode Island). The border zone was established by the U.S. DOJ in its interpretation of the Immigration and Nationality Act of 1952. Customs and Border Protection (CBP) officials have authority to stop and search within this zone and are authorized to enter private property without a warrant within 40 km (25 mi) of the border as well as establish checkpoints.

The Fourth Amendment of the U.S. Constitution protects against unreasonable search and seizure. However, under the border search exception, this protection does not fully apply at borders or border crossings (also known as ports of entry) or in the border zone. This means that much of the U.S. population is subject to CBP regulations including stop and search.

Transborder students

Entrance into Mexico at Nogales, AZ

Many schools near the border in America have students that live on the Mexican side of the border. These students are "transborder students", as they live in Mexico but are enrolled in the U.S. education system. There are thousands of elementary through high school students that cross the Mexican-American border. They are known to wake up in the early hours of the morning to make their way to the border, where they wait in long lines to cross into the U.S. After crossing the border, the students find a ride to school. Many students come to America for the opportunity, because it has a more developed and organized educational system. Students who go to school in America have a better chance of reaching higher education in the U.S. In many parts of Mexico, compulsory education ends at age sixteen. Many of the transborder students are natural-born U.S. citizens. Students that were born in America have the right to American education, even if they do not live in the U.S. In places like the San Diego and Tijuana border, it is much cheaper to live in Mexico. San Diego has a high cost of living and one of the highest student homeless rates in the country, so many families move to Tijuana because it is more affordable to raise a family.

In order to prevent Mexican children from illegally coming to America for education, some bordertown schools require official documentation (bills, mail, etc.) from students. This is to ensure that only students that are entitled to an education in the U.S. receive one.

See also

In Spanish: Frontera entre Estados Unidos y México para niños