What Is the US Border Enforcement Zone?

The authority of border patrol agents extends way beyond the southern border.

Published Jun 13, 2022

Image Via Wikipedia

In June 2022, a tweet went viral that supposedly showed a map of a 100-mile "border enforcement zone" and claimed that a recent U.S. Supreme Court ruling allowed border patrol agents to violate the Fourth Amendment in this area and "enter any home without a warrant and assault you."

The 100-mile border enforcement zone is real, but it wasn't recently created by a Supreme Court decision. Furthermore, border patrol is not explicitly allowed to "enter any home without a warrant" within this zone (the 100-mile rule generally applies to vehicles) and there are no laws that permit agents to assault people. That being said, the Supreme Court did recently rule against an individual who was suing a border patrol agent for violating Fourth Amendment rights by using excessive force.

What is the Border Enforcement Zone?

While many people may think of the "border" as the dividing line between the United States and Mexico, U.S. Customs and Border Protection (CBP) agents actually operate around the entire border of the United States. That includes the country's northern border with Canada, as well as the eastern, western, and southern coastlines.

This so-called "Border Enforcement one," as the meme called it, has been around since the 1950s, when the Immigration and Nationality Act of 1952 established that a "reasonable distance" of the border would extend "100-air miles" around the outline of the country.

According to 8 U.S. Code § 1357, employees of the United States Citizenship and Immigration Services (USCIS), Immigration and Customs Enforcement (ICE), and Customs and Border Patrol are granted certain "powers without warrant" within this area, such as the authority to "board and search for aliens" on any "railway car, aircraft, conveyance, or vehicle." This law also gives border patrol agents the authority to "access private lands, but not dwellings, for the purpose of patrolling the border to prevent the illegal entry of aliens into the United States." However, the law states that border patrol agents only have the authority to "access private lands" within 25 miles of the border, not 100 miles.

Here's how the American Civil Liberties Union (ACLU) described this border enforcement zone:

Are immigration officials allowed to stop people in places wholly inside the U.S.?
U.S. Customs and Border Protection, the federal agency tasked with patrolling the U.S. border and areas that function like a border, claims a territorial reach much larger than you might imagine. A federal law says that, without a warrant, CBP can board vehicles and vessels and search for people without immigration documentation 'within a reasonable distance from any external boundary of the United States.' These 'external boundaries' include international land borders but also the entire U.S. coastline.

What is a 'reasonable distance'?
The federal government defines a 'reasonable distance' as 100 air miles from any external boundary of the U.S. So, combining this federal regulation and the federal law regarding warrantless vehicle searches, CBP claims authority to board a bus or train without a warrant anywhere within this 100-mile zone. Two-thirds of the U.S. population, or about 200 million people, reside within this expanded border region, according to the 2010 census. Most of the 10 largest cities in the U.S., such as New York City, Los Angeles, and Chicago, fall in this region. Some states, like Florida, lie entirely within this border band so their entire populations are impacted.

The map included in the above-displayed tweet appeared to have originated with a 2020 article from the Southern Border Communities Coalition (SBCC), a border-policy advocacy group. This organization wrote at the time:

The U.S. Customs and Border Protection (CBP), which includes the Border Patrol, is the largest law enforcement agency in the country. The jurisdiction they claim spans 100 miles into the interior of the United States from any land or maritime border. Two-thirds of the U.S. population lives within this 100-mile border enforcement zone, including cities like Washington D.C., San Francisco CA, Chicago IL, New Orleans LA, Boston MA, & more.

Because these are considered border cities, federal border and immigration agents assert the power to board public transportation or set up interior checkpoints and stop, interrogate and search children on their way to school, parents on their way to work, and families going to doctor’s appointments or the grocery store — all done without a warrant or reasonable suspicion.

We reached out to CBP and we will update this article if more information becomes available.

Does the Border Zone Violate the Fourth Amendment?

The Fourth Amendment of the U.S. Constitution grants the "right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized." In short, it was designed to protect Americans against arbitrary arrests and requires law enforcement to obtain warrants before searching homes.

While performing searches without a warrant may seem like a violation of the Fourth Amendment, the Supreme Court has previously ruled that searches within the zone do not violate that amendment. In the 1976 case United States v. Martinez-Fuerte, for example, the Supreme Court ruled that immigration checkpoints within this zone were not a violation of the Fourth Amendment, writing that it would be "impractical" to require such stops to "always be based on reasonable suspicion" and that "brief questioning of the vehicle's occupants is consistent with the Fourth Amendment."

What Did the Supreme Court Rule in 2022?

The tweet above went viral in the days after the Supreme Court issued a ruling in the case of Egbert v. Boule, which dealt with an interaction between a border agent (Erik Egbert) and the owner of a bed and breakfast on the border of the United States and Canada (Robert Boule). This case did not establish or change the size of a new border zone. Rather, as The New York Times reported, the court ruled that only Congress could authorize lawsuits against federal agents for violating constitutional rights.

The New York Times reported:

The owner of an inn on the Canadian border who said he had been assaulted by a Border Patrol agent may not sue the agent for violating the Constitution by using excessive force, the Supreme Court ruled on Wednesday.

The decision, by a 6-to-3 vote along ideological lines, stopped just short of overruling a 1971 precedent, Bivens v. Six Unknown Named Agents, that allowed federal courts, rather than Congress, to authorize at least some kinds of lawsuits seeking money from federal officials accused of violating constitutional rights.

But the basic message of Wednesday’s decision, Egbert v. Boule, No. 21-147, was that only Congress can authorize such suits.

Here's an excerpt from Supreme Court Justice Clarence Thomas' opinion. Thomas wrote:

In Bivens v. Six Unknown Fed. Narcotics Agents, 403 U. S. 388 (1971), this Court authorized a damages action against federal officials for alleged violations of the Fourth Amendment. Over the past 42 years, however, we have declined 11 times to imply a similar cause of action for other alleged constitutional violations [...] Nevertheless, the Court of Appeals permitted not one, but two constitutional damages actions to proceed against a U. S. Border Patrol agent: a Fourth Amendment excessive-force claim and a First Amendment retaliation claim. Because our cases have made clear that, in all but the most unusual circumstances, prescribing a cause of action is a job for Congress, not the courts, we reverse.

Supreme Court Justice Sonia Sotomayor wrote a dissenting opinion in the Egbert v. Boule case, writing that the decision "closes the door" to lawsuits from those who "suffer serious constitutional violations at the hands of federal agents." Sotomayor referenced the border zone in her opinion, writing:

The consequences of the Court’s drive-by, categorical assertion will be severe. Absent intervention by Congress, CBP agents are now absolutely immunized from liability in any Bivens action for damages, no matter how egregious the misconduct or resultant injury. That will preclude redress under Bivens for injuries resulting from constitutional violations by CBP’s nearly 20,000 Border Patrol agents, including those engaged in ordinary law enforcement activities, like traffic stops, far removed from the border. [...] This is no hypothetical: Certain CBP agents exercise broad authority to make warrantless arrests and search vehicles up to 100 miles away from the border. See 8 U. S. C. §1357(a); 8 CFR §287.1(a)(2) (2021). The Court’s choice to foreclose liability for constitutional violations that occur in the course of such activities, based on even the most tenuous and hypothetical connection to the border (and thereby, to the “national security context”), betrays the context-specific nature of Bivens and shrinks Bivens in the core Fourth Amendment law enforcement sphere where it is needed most.

In Summary

The map in the tweet showing a "100-mile border enforcement zone" refers to the Border Patrol's authority to conduct warrantless searches in pursuit of "aliens" within a "reasonable distance" of the border. While the map was geographically accurate, the Supreme Court did not create this zone in June 2022.


“8 U.S. Code § 1357 - Powers of Immigration Officers and Employees.” LII / Legal Information Institute, Accessed 10 June 2022.

“100-Mile Border Enforcement Zone.” Southern Border Communities Coalition, Accessed 10 June 2022.

“ACLU Factsheet on Customs and Border Protection’s 100-Mile Zone.” American Civil Liberties Union, Accessed 10 June 2022.

“Congress Tackles the ‘100-Mile’ Border Zone for Federal Checkpoints.” Just Security, 30 July 2019,

“Know Your Rights in the 100 Mile Border Zone.” ACLU of New Mexico, 24 Sept. 2021,

Liptak, Adam. “Supreme Court Sides With Border Agent Accused of Using Excessive Force.” The New York Times, 8 June 2022.,

Millhiser, Ian. “The Supreme Court Gives Lawsuit Immunity to Border Patrol Agents Who Violate the Constitution.” Vox, 8 June 2022,

“The Constitution in the 100-Mile Border Zone.” American Civil Liberties Union, Accessed 10 June 2022.

“United States v. Martinez-Fuerte, 428 U.S. 543 (1976).” Justia Law, Accessed 10 June 2022. Accessed 10 June 2022.

Dan Evon is a former writer for Snopes.