The State of the Southern Border

Border Web Feature

President Trump has issued Executive Order 13767 “to immediately plan, design, and construct a physical wall along the southern border”—a border he referred to during his campaign as “a sieve.”1 The truth of the matter, however, is that the border between the United States and Mexico is currently more secure and protected than at any time in history. In fact, every border security standard outlined in the 2006 immigration reform bill—crafted when Republicans last held the White House and both chambers of Congress—has already been met, and in many cases exceeded. Far from an open door, the southern border has seen massive increases in enforcement spending, personnel, and hardware since 2000. To get an accurate picture of the state of the border, below we analyze the land it’s on, the physical barriers already erected there, the Border Patrol resources on-site, and the recent changes it has seen to immigration patterns.

1. The Land on Which the Border Is Located

The border between the United States and Mexico is not a straight line nor even all located on dry land. It presents unique challenges to people trying to cross it, and to the U.S. government that has had to adapt its approach to protecting it.

The geography of the border is diverse and challenging.

The U.S.-Mexico border is 1,954 miles long, reaching from the Pacific Ocean in the west to the Gulf of Mexico in the east.2 On the U.S. side, the land surrounding the border is home to approximately 7.3 million people, according to the 2010 Census. Crossing California, Arizona, New Mexico, and Texas, the border spans nearly every type of terrain, including cities, farmlands, deserts, mountains, valleys, reservoirs, and even a National Park. The majority of the border—1,254 miles or 63%—is marked by the Rio Grande River, which flows up to 500 feet wide and 60 feet deep at certain points.3

Most of the land on the border isn’t owned by the federal government.

Only one-third of the land on which the southern border is located is owned by the federal government or Native American tribes—the rest is largely state property or farmland owned by individual ranchers.4 Sixty-six percent of the total land on the border is owned by states or individuals, most of which is located along the Rio Grande River in Texas.5 That means in order to build any structures there, the federal government must either receive permission from each individual landowner whose property will be affected or must exercise its powers of eminent domain to take possession of the land. Eminent domain law allows the government to forcibly take privately-owned land for public use—even over the objections of the owners—so long as they are reimbursed for the fair value of the land. While the federal government has the power to use eminent domain for public projects, it is extremely unpopular both in Congress and with the public, and court challenges from landowners can stall the process for years and cost the government millions of dollars in legal costs.6 The last time the federal government undertook construction of a fence on the southern border, hundreds of lawsuits were filed by private landowners.7 And in many cases, once the land had been seized and fencing built, farmers saw their crops torn out, and they ended up living in a “no-man’s land” south of the existing fence. 8

International treaty obligations limit government action on much of the border.

Not only is the border complicated by its topography and ownership, it is also subject to international treaty law. In 1970, the United States and Mexico signed a treaty that restricts construction along the Rio Grande and prohibits disrupting the river’s natural flow. Because the river itself is the border between the United States and Mexico, any changes to its flow or course can alter the boundary between the countries.9 As a result, both countries are restricted from building in the river or within its flood plain if doing so would increase flooding on its banks or affect the course of the river. Establishing any physical barriers along the Rio Grande requires either joint approval from the U.S. and Mexico via the International Boundary and Water Commission or that any structure be built sufficiently inland to avoid impacting the river.10 This treaty obligation significantly curtails where and how a physical barrier can be constructed along much of the southern border, and in many cases, it requires the government of Mexico to approve of structures built even on the U.S. side.

2. Existing Physical Barriers at the Border

Roughly 38% of the U.S.-Mexico border is currently fenced—most of which is concentrated in California, Arizona, and New Mexico where the border is on land. In total, the U.S. government has spent $7 billion dollars building roughly 700 miles of fencing along the border since 1990. The majority of that fencing—670 miles—has been built since 2006, when Congress passed the Secure Fence Act, the same legislation President Trump relies on in his executive order to claim authority to build his wall.11 The 670 miles of fencing built in the last decade already satisfy the requirements outlined in the 2006 immigration reform bill, which called for 370 miles of fencing and 300 miles of vehicle barriers.12 As such, the Department of Homeland Security has not requested authorization or funding for additional fence construction in any of its recent budget requests sent to Congress. 13

The most highly-trafficked and regularly-crossed areas of the border are protected by physical barriers.

The U.S. government has established physical barriers along the border in those locations with lots of people and heavy traversing of the border. Much of the fence has been constructed in the densely-populated border areas in California, Arizona, and New Mexico. To date, the federal government has fenced in the majority of the border along those three states. All of the largest cities located along the border—including San Diego, Yuma, El Paso, Laredo, McAllen, and Brownsville—now have fencing built along the border areas closest to them.14

The sections of the border that remain unfenced today largely fall into one of two categories: the Rio Grande River itself, or desert and mountainous areas where immigrants are less likely to attempt to cross the border.15 Building in these remote areas or on the river would be significantly more difficult and expensive than in those places where barriers have already been erected.16 It’s estimated that construction of a border fence in these remote locations could cost roughly $16 million per mile—about six times more than it cost to build the fence spanning the rest of the border.17 Border Patrol deploys its resources where they are most needed, rather than spreading them evenly across the border. That’s why places with the highest proportions of apprehensions, like the Rio Grande Valley in the southern tip of Texas and Tucson, Arizona—heavily populated regions where the majority of immigrants attempt to cross the border—have seen significant barrier and fencing construction in the last decade.18

The border is protected by fencing, vehicle barriers, and state of the art technology.

The U.S. government uses several different types of barriers and fencing along the southern border, depending on location, need, and purpose. Fencing is used in areas of high population density and is intended to prevent pedestrian border crossing. Three general types are used: metal mesh, bollard (pillars placed closely together), and solid metal fencing, and they can range in height from 10 feet to more than 20 feet high.19 In some particularly high-trafficked areas, double layers of fencing have been constructed to provide increased obstruction.

Vehicle barriers are also used at the southern border, typically in more remote areas where foot traffic is lower and immigrants are more likely to approach by car or truck. These can either be several foot high pillars or steel anti-tank style barriers, both of which prevent cars from being able to pass.20

In addition to fences and anti-vehicle barriers, the U.S. government also relies on technology as a “virtual fence” to guard the border. The Border Patrol increasingly utilizes towers, cameras, radar, and dirigibles (blimp-like aircraft) to monitor the border and prevent unauthorized crossing. Today, the border has been outfitted with hundreds of these structures and devices, including:

  • Permanent integrated fixed towers fitted with cameras, radios, and microwave transmitters that allow the Border Patrol to monitor multiple portions of the border from a central command area;21
  • Movable towers equipped with similar cameras and transmitters that can be stationed and relocated as needed;22
  • Blimp-like radar vehicles called Tethered Aerostat Radar Systems that monitor air traffic within a 200 mile range; and,23
  • More than 12,000 motion sensors and hundreds of remote video or mobile surveillance systems.24

3. Increased Border Patrol Size & Resources

Customs and Border Protection, tasked with enforcing American immigration policy at its borders, is the largest federal law enforcement agency in the country. The federal government spends more on border and immigration enforcement than on all of the other federal law enforcement agencies combined. Today that amount is nearly $20 billion per year—a 12-fold increase since the 1990s.25

The Border Patrol has quadrupled in size since 2001.

Within Customs and Border Protection, the Border Patrol is tasked with intercepting and detaining undocumented immigrants entering the United States. During the past two presidential administrations, the Border Patrol has grown extensively both in budget and personnel. Annual federal spending on the border has nearly quadrupled in the last 15 years, from $1.1 billion in 2001 to nearly $4 billion today.26 And in that time, Congress has also authorized an additional $1.5 billion to increase security at border checkpoints.27

At the beginning of the George W. Bush Administration, the Border Patrol employed roughly 4,000 agents. By the time the Obama Administration took office, that number had increased to 9,000. Today there are more than 21,000 Border Patrol agents—a number that even exceeds the build-up written into President Bush’s immigration bill in 2006. Seventeen thousand of those agents are currently deployed along the border between the United States and Mexico, including hundreds on horseback who patrol rugged terrain otherwise difficult to access. 28

Border Patrol vehicle and equipment inventories are at all-time highs.

The Border Patrol build-up has not been limited to budget and manpower—today it marshals more equipment than ever before, much of which is used at the southern border. As with nearly every other measure, this equipment increase has exceeded the requirements laid out in the immigration reform deal in 2006. That bill, for instance, required Border Patrol to deploy four drones at the southern border—today nine are in use, in addition to 254 aircraft and 295 marine vessels.29

One reason for this increase in Border Patrol equipment inventories is the use of the Pentagon’s 1033 surplus program. Created in 1996, this program allows the Pentagon to distribute excess military equipment to law enforcement agencies and departments across the nation.30 In recent years, the program has been scrutinized for providing military-grade hardware to local police departments, but in truth much of the equipment—and in the early years nearly all of it—has been given to the Border Patrol and the southern border. This includes everything from weapons and night vision goggles to office supplies. For example, one single Homeland Security and Customs and Border Protection coordination center in El Paso, Texas, has been given over $38 million worth of equipment since 2006. Between 2009 and 2014 alone, it received 46,270 magazine cartridges, 3,178 ammunition chests, 2,903 pairs of ballistic goggles, and 1,969 combat goggles.31In total, the Department of Homeland Security has received well over 300,000 pieces of equipment from the Pentagon.32

4. Changing Immigration Patterns

Migration trends along the southern border have shifted appreciably since the federal government increased spending on border enforcement during the Bush and Obama Administrations.

The number of apprehensions at the southern border has fallen significantly.

As Border Patrol spending and staffing has multiplied over the past two presidencies, the number of undocumented immigrants coming to the United States has fallen. This means more money is spent reinforcing the border against a much smaller pool of would-be crossers. Today, apprehensions of undocumented immigrants from Mexico and South America are at near-historic lows.33 Mexican immigrants currently account for about half of apprehensions along the southern border, so their numbers are highly illustrative.34 In 2000, the Border Patrol apprehended more than 1.6 million Mexican nationals attempting to cross the border into the United States without authorization. But by 2015, that number had fallen to only 188,000—a reduction of nearly 90%.35

Net immigration from Mexico is so low, it’s becoming negative.

In recent years, net immigration from Mexico has decreased substantially—both among authorized and unauthorized immigrants. While Mexican nationals still make up a sizable portion of the foreign-born population in the United States—28%—that proportion is shrinking.36In 2009, it was estimated that 6.4 million undocumented immigrants from Mexico were living in the United States, but by 2014 that number had fallen 9% to 5.8 million. And the number of Mexican immigrants legally entering the United States each year has steadily declined, from 1.4 million in 2006 to 390,000 in 2011. Since then, annual immigration numbers from Mexico have hovered around 400,000 per year. As the Mexican economy has improved, more Mexicans living in the United States have returned home, creating a reverse-immigration scenario. While thousands of Mexicans still come to the United States each year, from 2009 to 2014 about 130,000 more Mexican nationals left the United States than entered it.37

Migration models are shifting away from unauthorized southern border crossings.

While undocumented immigrants from Mexico and South America do account for a considerable portion of unauthorized immigration to the United States, that is beginning to change as immigration patterns evolve in the new century. Today, immigrants from Asia account for a larger proportion of immigration to the U.S. (documented and undocumented combined) than immigrants from Mexico.38 When it comes to undocumented immigration alone, it’s estimated that roughly 40% of undocumented immigrants currently in the country entered legally and simply failed to leave once their visas expired.39 More and more, migration patterns into the United States are trending away from entries at the southern border and towards air and sea ports.


Today the southern border is the most secure it has ever been in the history of our nation. Border security spending is at an all-time high, while immigration is stagnant and apprehensions are nearing historic lows. Increases in border security in the last 16 years have revolutionized what the border looks like, how it is protected, and the ways in which people enter the United States. There is no doubt the country’s immigration system is broken, but its flaws do not lie along the border with Mexico. President Trump’s executive order requiring construction of a wall across the border will cost taxpayers upwards of $25 billion, without making them any safer or the border any more secure. That undertaking is akin to building a wall from San Diego, California, to Chicago, Illinois—and it would be about as effective.

End Notes