During his 2016 presidential campaign, Donald Trump made his chant “Build the wall” a rallying cry for his far-right supporters. Now that he is back in office, will he pick up where he left off after failing to complete the wall during his first term? How much will it cost to complete, and is it a realistic possibility at all?

Such a huge project like the southern border wall doesn’t get built overnight and costs huge amounts of money and manpower not only to build but also to maintain and patrol. We looked into the data provided by the government and independent agencies to find out what it would cost to complete and the impact that completion would have on immigration.

Background on the Southern Wall

Trump’s Campaign Promises vs. Reality

As he began work on the southern border wall, Donald promised his supporters that, “You’re going to have a wall like no other. It’s going to be a powerful, terrific wall… A very big and very powerful border wall is going up at a record speed, and we are fully financed now, isn’t that nice?”

However, reality, as usual, didn’t quite match the promises he made. Even before he left office, the wall had fallen far behind schedule and exceeded budget projections.

Prior to Trump, Presidents Bush and Obama had both constructed hundreds of miles of border walls and other protections along various parts of the 1,954-mile border with Mexico.

Bush’s wall construction cost around $4 million per mile to build and Obama’s contribution cost around $20 million per mile.

Trump’s construction plan was estimated to cost $25 billion in total, but by 2020 the cost had already exceeded $11 billion and wasn’t halfway finished, already putting the cost at about $20 million per mile, with the 204 miles of wall in Arizona estimated to cost $4.5 billion alone.

Additionally, of the 458 miles of fencing he managed to build, most of it replaced existing barrier structures with a taller wall. Including sections already built by Bush and Obama, the new wall would only cover around 3/5 of the entire border.

Extent of Existing Border Barriers

Breaking it down, there were 354 miles of existing pedestrian fencing (meant to prevent illegal immigration by foot) before Trump. During his administration, he replaced 176 miles of fence and built only 87 miles of new fencing.

Trump’s pedestrian fencing, or border wall, includes some now-iconic features. It is 30 feet tall in most places with six-inch wide bollards spread six inches apart with steel anti-climbing plates at the top. The wall extends between six to ten feet underground and includes fiber optics to detect digging, and LED lights to help spot activity at night.

The wall is expected to last for only 30 years with regular maintenance.

Maintenance and Durability

This makes Trump’s wall the tallest and most expensive wall ever built on Earth, with second place being the wall Israel built in the West Bank to maintain and enforce its apartheid state, costing only $1 million to $5 million per mile to build.

Today, less than half of the southern border is protected by some form of barrier.

State-Led Initiatives

In 2021, Texas Governor Greg Abbot attempted to aid in construction by building his own section of the wall along the Texas border. The entire Texas-Mexico border stretches 1,200 miles and Abbot’s plan was to build 800 miles of border wall. By 2024 he had built only 34 miles (around 4% of the planned 800) at a cost of $25 million per mile. At this rate, it will take 30 years and $20 billion more to finish just that 800 miles.

In 2022, Arizona Governor Doug Ducey tried to join the party and score easy political points by ordering a makeshift wall built of shipping containers. The state began construction in the Coronado National Forest without authorization by the U.S. Forest Service. The wall violated the Endangered Species Act and the U.S. Justice Department sued the state and forced it to repay the government for any cost needed to undo Ducey’s decision.

What Will It Cost?

Trump promised to build a southern wall and “make Mexico pay for it” but, as usual, the American people were the ones left duped and paying the price.

In January of 2025, Trump declared a state of emergency to help secure funding for the border wall, and Republican congressmen introduced the Wall Act which would set aside an additional $25 billion to help finish the original plan.

Projected Budgetary Burden

This is on top of what was already spent on upgrading existing walls and fences and only for the announced plans.

According to Time, some of the highest estimates for the total cost of building barriers along applicable sections of the border reach as high as $70 billion.

This does not include the cost of acquiring land, however. Much of the land adjacent to the border is owned by private citizens or companies. Seizing this land through eminent domain involves the work of multiple agencies like the Department of Justice and can spiral into years of expensive lawsuits and legal costs.

Land Acquisition Hurdles

If the Trump administration wants to actually build a wall along the entire southern border, as it promised, it is expected the cost will far exceed the $70 billion estimate, which is about $200 for every American citizen.

This doesn’t take into account, however, the cost of the economic impact of the wall.

Broader Economic Considerations

According to researchers, undocumented or illegal immigrants actually increase the size of the U.S. economy, help the economy grow faster, enhance the welfare and living conditions of U.S. citizens overall, pay more taxes than they collect in any benefits or services, and reduce the cost of domestic-produced goods.

Illegal or undocumented immigrants also commit less crime overall, and at a lower rate, than native-born U.S. citizens and legal immigrants. Also, sanctuary cities have no statistical impact on the crime in their area and immigration enforcement has had no impact on crime rates.

In 2022 alone, families or households led by undocumented immigrants paid $75.6 billion in taxes, and they won’t take any of that back in Social Security and Medicare. Essentially, illegal immigrants pay for the entire cost of the wall each year in taxes themselves.

The construction of a wall must take these economic factors into account.

Will it Help with Illegal Immigration?

As with all things that don’t exist, there is no concrete answer yet, but there is plenty of passionate debate about whether the wall will help with the issues Donald Trump has said stem from a porous border: drugs and illegal immigration.

With regard to illegal immigration, the answer is probably not.

2024 had the lowest number of illegal border crossings since 2020, and illegal border crossings overall have declined by considerable amounts since 2000. Most of the undocumented immigrants within the United States are actually visa overstays, not people who crossed the border.

With regard to drugs being smuggled into the country, the answer is definitely not.

According to the Brookings Institute, and the U.S. Government itself, almost all of the illegal drugs smuggled into the United States don’t come with migrants who cross the border illegally, but with U.S. citizens who pass through legal ports of entry.

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