The Trump Era

The wall: Building a continuous US-Mexico barrier would be a tall order

The U.S.-Mexico border fence system today. Pedestrian fence is colored dark orange, vehicle fence in light orange. Credit: Reveal research, U.S. Customs and Border Protection, OpenStreetMap, Allison McCartney

Building the border wall has been central to President Donald Trump’s promises and it will be central to Reveal from The Center for Investigative Reporting’s coverage this year. We will be exploring the feasibility of various proposals as they emerge.

Trump has said a lot of things about that wall, but it’s still not clear exactly what he means.

We do know a lot about the current border fence, though, because we’ve been collecting and analyzing data on it for years. Based on that, here’s a rundown of the job the new president has ahead of him.

Is what we have now a wall or a fence?

If by a wall, you mean a large vertical structure that’s not full of holes, then the current border barrier is definitely a fence, or rather a series of fences. There are many types of fence along the U.S.-Mexico border.

Some sections are tall and are designed to block people from entering on foot – so-called pedestrian fence.

Examples of pedestrian fence along the U.S.-Mexico border. Credit: U.S. Customs and Border Protection

Other large sections of the fence are only a few feet tall and can be climbed over easily. These sections, designed to stop vehicles from crossing, stretch across more remote areas where it would be difficult to cross the border safely on foot.

Examples of vehicle fence on the U.S.-Mexico border. Credit: U.S. Customs and Border Protection

Where is the border fenced today?

It depends on whom you ask. Many numbers have been suggested by government agencies, and Customs and Border Protection for years refused to release detailed spatial data about fence locations. In 2012, we started tracing the border fence using open-source mapping tools.

Later, Denise Gilman, a law professor at the University of Texas at Austin, sued the government under the Freedom of Information Act to obtain detailed PDF maps of the fence systems. (In an illustration of just how difficult FOIA work can be, she told Reveal that she filed her initial request in 2008 but didn’t get final maps until 2013.)

Reveal spent the first weeks of this year converting those PDFs into digital maps that can be used for analysis, combining it with our previous fence work to create the most detailed border fence map publicly available.

According to our new map, there are 700 miles of fence along the U.S.-Mexico border – a Customs and Border Protection spokeswoman recently said the total is 702, so our tally is very close to the agency’s. However, in some high-traffic spots, there are two or three layers of fence in one place, leaving somewhere between 652 and 690 miles of the border actually covered by fence.

The U.S.-Mexico border fence system today. Pedestrian fence is colored dark orange, vehicle fence in light orange. Credit: Reveal research, U.S. Customs and Border Protection, OpenStreetMap, Allison McCartney

Those miles are divided into at least 385 miles of pedestrian fence and at least 301 miles of vehicle fence. (That leaves a few miles unclassified, which are clearly fenced but don’t appear on the Customs and Border Protection maps obtained through public records requests.)

Many shorter segments of fencing have been built along the border since the early 1900s. The Clinton administration built about 19 miles at the San Diego-Tijuana border. Then, George W. Bush spearheaded the biggest expansion, which led to the construction of 523 miles of fence.

Today, the San Diego-Tijuana boundary has the most elaborate fencing system, with multiple layers of pedestrian fence in some places.

Multiple layers of pedestrian fence between San Diego and Tijuana. Credit: Reveal research, U.S. Customs and Border Protection, OpenStreetMap, Google Earth/Digital Globe

But in remote areas, a single strand of vehicle fence can be the only marker of the international boundary.

Vehicle fence in southern Arizona, just north of a road in Sonora, Mexico. Credit: Google Earth/DigitalGlobe

Where is there no fence at all?

Most of the border – 65 percent of the nearly 2,000-mile border – has no fence. In its place are natural barriers such as rivers, cliffs and mountains that make it difficult to cross or difficult to build. Some of these are places with so little movement across the border that previous administrations have deemed a barrier unnecessary.

The 1,288 miles along the U.S.-Mexico border with no fence are outlined in purple. Credit: Reveal research, U.S. Customs and Border Protection, OpenStreetMap, Allison McCartney

The biggest unfenced sections are in Texas, where the Rio Grande River forms a natural barrier. Other large gaps are in remote parts of New Mexico and Arizona.

Here and there, the fence also has smaller stops and starts.

A mountain cuts through sections of border fence southeast of Yuma, Arizona. Credit: Google Earth and Matt Stiles/NPR

The Eagle Pass Municipal Golf Course in Eagle Pass, Texas, is sandwiched between the Rio Grande River and sections of border fence approved during George W. Bush’s presidency. Credit: Reveal research, U.S. Customs and Border Protection, OpenStreetMap, Google Earth/Digital Globe

What has Trump said that he wants?

In February 2016, Trump told MSNBC that the wall would be approximately 1,000 miles long, because “we have natural barriers” that mean a fence along the other 1,000 miles isn’t necessary.

Most other estimates of the cost to build Trump’s wall are much higher than his $8 billion figure. Writing in MIT Technology Review, Konstantin Kakaes estimated that the construction costs for a 1,000-mile concrete fence would range from $30 billion to over $40 billion. This cost would not include demolishing existing fence to replace it with a new wall, if Trump chooses to do that instead.

The Washington Post estimated $42 billion for 1,000 miles of a 25-foot wall.

For comparison, the United States’ newest aircraft carrier cost about $13 billion. So estimates for the fence range from 0.6 aircraft carriers to 3.2 aircraft carriers.

But, much like an aircraft carrier, construction is far from the only cost involved. Maintenance has been a constant headache along the border fence. Besides wear and tear from being exposed to the elements, people often cut through or damage the fence intentionally. New roads will need to be built to expand the system, and those roads also will need to be maintained.

Damaged and repaired border fence, seen from the Tijuana airport. Credit: Michael Corey/Reveal

According to a March 2016 U.S. Government Accountability Office study, U.S. Customs and Border Protection reported that maintaining the existing fence cost the department at least $7.2 million in 2010.

Michael Corey can be reached at, and Andrew Becker can be reached at Follow them on Twitter: @mikejcorey and @ABeckerReveal.

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