Migrant encounters at the U.S.-Mexico border have fallen to lows not seen since the 1960s. In April, the U.S. Border Patrol reported intercepting fewer than 8,400 irregular crossers—a stark contrast from the record high of nearly 250,000 encounters witnessed in December 2023. And data picked up elsewhere in the Western Hemisphere suggest unauthorized migration headed northward is slowing across the region: Reporting from the Darien Gap, the treacherous jungle that divides Panama and Colombia, shows there were just 200 crossings in March, compared to more than 37,000 the same month a year earlier.
With these near-historic lows, the Trump administration can rightfully claim that it has secured the border at this time, building on declines that began in early 2024 and accelerated in the second half of the year. The longer-term test, however, is whether this success can be sustained through the administration’s new show of force alone, without the less visible migration management ingredients that led to the quieting border the administration inherited.
A Year-Long Story of Reduced Migrant Flows
The current lows build on a pattern of reduced irregular arrivals that started with changes in Biden administration policies in early 2024. Amid the record level of Southwest border arrivals witnessed in December 2023, which came on the heels of two years of record border encounters during the Biden administration, the U.S. and Mexican governments negotiated increased Mexican enforcement at Mexico’s northern border and throughout the country, including checkpoints throughout well-traveled interior routes.
With this ongoing additional enforcement from Mexico, irregular arrivals at the U.S.-Mexico border decreased by 53 percent between December 2023 and May 2024 (see Figure 1). The impact of Mexican enforcement cannot be overstated: Mexican authorities recorded more encounters than did the U.S. Border Patrol every single month between May 2024 and March 2025 (the most recent month for which Mexican enforcement data are available).
Figure 1. Irregular Migrant Encounters by U.S. Border Patrol at U.S.-Mexico Border, 2023–25
Note: The data here reflect encounters recorded by the U.S. Border Patrol of migrants crossing the border without authorization; U.S. Customs and Border Protection (CBP) Office of Field Operations encounters of migrants arriving at a U.S. port of entry without prior authorization to enter are not included here. Source: CBP, “CBP Nationwide Encounters,” accessed May 29, 2025.
Following implementation of the Biden administration’s June 2024 Secure the Border rule, irregular encounters continued to drop, with the ongoing aid offered by increased Mexican enforcement. This rule sought to disincentivize illegal entries and incentivize arrivals at a port of entry by further limiting access to asylum for those who crossed between ports of entry and permitting an appointment, through use of the CBP One app, to be screened at an official port of entry. Those who entered through the CBP One app could later go on to apply for asylum.
Irregular crossings dropped from 84,000 that June to 47,000 in December, a 43 percent decrease. Notably, encounters in December 2024 were 81 percent lower than the same month a year earlier. Proof that the carrot-and-stick approach was beginning to turn the tide was seen in November 2024, when for the first time more migrants arrived at ports of entry than between (see Figure 2). Though by a small margin, this shift established a pattern of more migrants seeking to enter lawfully via CBP One rather than risk entering irregularly.
Figure 2. Migrant Encounters At and Between Ports of Entry at U.S.-Mexico Border, 2024
Note: Office of Field Operations (OFO) encounters occur at ports of entry; U.S. Border Patrol encounters occur between ports of entry. Source: CBP, “CBP Nationwide Encounters.”
Inheriting an Increasingly Quiet Border
Thus, the current lows seen under the Trump administration represent a continuation of trends established during the prior administration—and momentum the Biden team put in place by increasing migration management cooperation with Mexico and other countries in the Western Hemisphere as well as further narrowing access to asylum at the U.S.-Mexico border. However, upon taking office, the Trump administration shuttered many of the programs that had become the basis for dramatic reductions in irregular arrivals.
During his first days in office, President Donald Trump declared a national emergency at the border and a migrant “invasion.” By cancelling use of the CBP One app while leaving the Secure the Border rule restrictions in place, the Trump administration made asylum inaccessible at the U.S.-Mexico border.
Most notably, the administration terminated access to Biden-era humanitarian pathways that had helped reduce chaotic arrivals at the Southwest border. The Trump administration swiftly ended admissions under the Cuban, Haitian, Nicaraguan, and Venezuelan (CHNV) parole program, which reduced irregular encounters of those nationalities at the border by 92 percent between October 2022 and December 2024. Nearly 532,000 individuals were admitted through the CHNV program, allowing them access to work permits and temporary relief from deportation. The administration also closed the Safe Mobility Offices (SMOs) that had been set up in Colombia, Costa Rica, Ecuador, and Guatemala to consider migrants for refugee resettlement or other lawful pathways before they reached the U.S. border. More than 40,000 people were approved for U.S. refugee status through the SMOs.
A Muscular Show of Force
Since taking office, the Trump administration has dramatically increased the military presence at the border, deploying nearly 10,000 military personnel to the area and for the first time ever placing swaths of borderland under the control of the Department of Defense in Texas, New Mexico, Arizona, and California. These “National Defense Areas” allow the military to arrest individuals who enter the territory on charges of trespassing on a military base and to detain them until they are turned over to CBP. At sea, Coast Guard cutters have been dispatched to monitor common migrant routes in the Florida waters and in the Gulf of Mexico (since renamed the Gulf of America by the administration) and in the Pacific between the United States and Mexico.
This show of force, coming alongside a highly publicized arrest and deportations initiative that has seen showy enforcement operations in U.S. cities and unauthorized immigrants flown to a high-security prison in El Salvador and put on military planes to India and other destinations, is undoubtedly acting as a further deterrent to would-be irregular border crossers. Indeed, some would-be migrants who had been waiting in Mexico for a hoped entry into the United States have begun making the dangerous journey in reverse, retracing their steps though the Darien Gap en route to their home country or other destinations in South America.
Finding the Formula for Sustained Lows
The Trump administration is also using fundamentally different tactics in engaging with the region. Under President Joe Biden, the U.S. government promoted the Los Angeles Declaration on Migration and Protection, a regional dialogue that called for cooperation and regional management within the hemisphere to curtail mass migration. Though it may not be the formula, the declaration offered building blocks for a well-managed migration system in the region stretching from Chile to Canada. In contrast, the Trump administration has threatened tariffs unless countries such as Mexico and Canada increase migration controls and others, such as Panama and Costa Rica, agree to accept third-country nationals deported by the United States.
The quiet border has led Homeland Security Secretary Kristi Noem to declare that the administration “has almost 100% operational control of the border,” which the Department of Homeland Security (DHS) now defines as getting Border Patrol agents back into the field rather than processing migrants. The first Trump term itself offers some evidence, though, that successes at the border cannot be sustained over time.
The early months of the first Trump term saw directives to build a border wall, increase detention capacity, and end “catch and release” (the term used to describe the release into the U.S. interior of those apprehended at the U.S.-Mexico border after processing). Coupled with strong anti-immigration rhetoric, the measures did initially cause irregular encounters to decrease (see Figure 3). However, within months of Trump taking office in 2017, border encounters were once again on the rise.
Figure 3. Irregular Migrant Encounters by U.S. Border Patrol at U.S.-Mexico Border, 2017–21
Note: The 2021 data are for January. Source: Data for 2017-20 can be found at CBP, “U.S. Border Patrol Monthly Encounters (FY 2000-FY 2020),” accessed May 29, 2025. Data for 2021 can be found at CBP, “CBP Nationwide Encounters.”
In reaction to the increased border arrivals, the Trump administration in May 2018 implemented the zero tolerance policy that resulted in more than 5,000 children being separated from their parents by the U.S. government. In January 2019, it implemented the Migrant Protection Protocols (MPP, often known as Remain in Mexico), which required more than 80,000 would-be asylum seekers to wait in Mexico, in often difficult conditions, for the duration of their case.
While these policies caused brief decreases in border encounters, their impacts were not long-lasting. For example, following implementation of the zero tolerance policy, migrant encounters decreased for just two months before rising to levels higher than before the policy was put in place. And after the implementation of MPP, irregular encounters reached their highest level of the Trump administration. Even after the onset of the COVID-19 pandemic, which shut borders around the world, and the implementation of Title 42—a public health authority that allowed for immediate expulsions—irregular encounters dropped only briefly before rising once again (see Figure 3).
Refocusing on Border Management
Movements to the U.S.-Mexico border are dynamic and depend upon much more than U.S. policy. Changing economic situations, war, regional or global policy changes, and political upheaval are among the factors that can affect the ability of the U.S. government to respond to changing migration patterns.
Though encounter levels at the U.S.-Mexico border are near historic lows, history shows that migration never fully stops. Rather, it adjusts to changing environments. The narrowing of humanitarian pathways and increased enforcement, at U.S. borders and in the interior, may have reduced encounters for now. But it could also expand business for smugglers to facilitate covert entry, perhaps via tunnels under the border or maritime routes, or shift crossings to more remote areas that have been quiet over recent years.
Given that migrant crossings are affected by myriad variables outside of U.S. policy control, the focus ought to be on effectively managing the flow to the border rather than seeking to stop it in its tracks—an historically unreachable goal as demonstrated by regularly occurring spikes in irregular arrivals (see Figure 4), in administrations Democratic and Republican alike, despite a consistent trendline over the past nearly four decades of ever increasing resources and authorities at the border.
Figure 4. Irregular Migrant Encounters by U.S. Border Patrol at U.S.-Mexico Border, FY 1996–2025*
Changing realities at the border, including litigation that could threaten the viability of some current border policies, will test the Trump administration’s ability to manage migration solely through a deterrence-focused approach. During the first Trump administration, such strategies resulted in short-term declines in encounters but did not provide for sustained lows. In unraveling key policies that contributed to establishing today’s quiet border, the administration is gambling with the possibility of increased irregular arrivals in the future.
Can Near-Historic Low Migrant Encounter Levels at the U.S.-Mexico Border Be Sustained?
Migrant encounters at the U.S.-Mexico border have fallen to lows not seen since the 1960s. In April, the U.S. Border Patrol reported intercepting fewer than 8,400 irregular crossers—a stark contrast from the record high of nearly 250,000 encounters witnessed in December 2023. And data picked up elsewhere in the Western Hemisphere suggest unauthorized migration headed northward is slowing across the region: Reporting from the Darien Gap, the treacherous jungle that divides Panama and Colombia, shows there were just 200 crossings in March, compared to more than 37,000 the same month a year earlier.
With these near-historic lows, the Trump administration can rightfully claim that it has secured the border at this time, building on declines that began in early 2024 and accelerated in the second half of the year. The longer-term test, however, is whether this success can be sustained through the administration’s new show of force alone, without the less visible migration management ingredients that led to the quieting border the administration inherited.
A Year-Long Story of Reduced Migrant Flows
The current lows build on a pattern of reduced irregular arrivals that started with changes in Biden administration policies in early 2024. Amid the record level of Southwest border arrivals witnessed in December 2023, which came on the heels of two years of record border encounters during the Biden administration, the U.S. and Mexican governments negotiated increased Mexican enforcement at Mexico’s northern border and throughout the country, including checkpoints throughout well-traveled interior routes.
With this ongoing additional enforcement from Mexico, irregular arrivals at the U.S.-Mexico border decreased by 53 percent between December 2023 and May 2024 (see Figure 1). The impact of Mexican enforcement cannot be overstated: Mexican authorities recorded more encounters than did the U.S. Border Patrol every single month between May 2024 and March 2025 (the most recent month for which Mexican enforcement data are available).
Figure 1. Irregular Migrant Encounters by U.S. Border Patrol at U.S.-Mexico Border, 2023–25
Note: The data here reflect encounters recorded by the U.S. Border Patrol of migrants crossing the border without authorization; U.S. Customs and Border Protection (CBP) Office of Field Operations encounters of migrants arriving at a U.S. port of entry without prior authorization to enter are not included here.
Source: CBP, “CBP Nationwide Encounters,” accessed May 29, 2025.
Following implementation of the Biden administration’s June 2024 Secure the Border rule, irregular encounters continued to drop, with the ongoing aid offered by increased Mexican enforcement. This rule sought to disincentivize illegal entries and incentivize arrivals at a port of entry by further limiting access to asylum for those who crossed between ports of entry and permitting an appointment, through use of the CBP One app, to be screened at an official port of entry. Those who entered through the CBP One app could later go on to apply for asylum.
Irregular crossings dropped from 84,000 that June to 47,000 in December, a 43 percent decrease. Notably, encounters in December 2024 were 81 percent lower than the same month a year earlier. Proof that the carrot-and-stick approach was beginning to turn the tide was seen in November 2024, when for the first time more migrants arrived at ports of entry than between (see Figure 2). Though by a small margin, this shift established a pattern of more migrants seeking to enter lawfully via CBP One rather than risk entering irregularly.
Figure 2. Migrant Encounters At and Between Ports of Entry at U.S.-Mexico Border, 2024
Note: Office of Field Operations (OFO) encounters occur at ports of entry; U.S. Border Patrol encounters occur between ports of entry.
Source: CBP, “CBP Nationwide Encounters.”
Inheriting an Increasingly Quiet Border
Thus, the current lows seen under the Trump administration represent a continuation of trends established during the prior administration—and momentum the Biden team put in place by increasing migration management cooperation with Mexico and other countries in the Western Hemisphere as well as further narrowing access to asylum at the U.S.-Mexico border. However, upon taking office, the Trump administration shuttered many of the programs that had become the basis for dramatic reductions in irregular arrivals.
During his first days in office, President Donald Trump declared a national emergency at the border and a migrant “invasion.” By cancelling use of the CBP One app while leaving the Secure the Border rule restrictions in place, the Trump administration made asylum inaccessible at the U.S.-Mexico border.
Most notably, the administration terminated access to Biden-era humanitarian pathways that had helped reduce chaotic arrivals at the Southwest border. The Trump administration swiftly ended admissions under the Cuban, Haitian, Nicaraguan, and Venezuelan (CHNV) parole program, which reduced irregular encounters of those nationalities at the border by 92 percent between October 2022 and December 2024. Nearly 532,000 individuals were admitted through the CHNV program, allowing them access to work permits and temporary relief from deportation. The administration also closed the Safe Mobility Offices (SMOs) that had been set up in Colombia, Costa Rica, Ecuador, and Guatemala to consider migrants for refugee resettlement or other lawful pathways before they reached the U.S. border. More than 40,000 people were approved for U.S. refugee status through the SMOs.
A Muscular Show of Force
Since taking office, the Trump administration has dramatically increased the military presence at the border, deploying nearly 10,000 military personnel to the area and for the first time ever placing swaths of borderland under the control of the Department of Defense in Texas, New Mexico, Arizona, and California. These “National Defense Areas” allow the military to arrest individuals who enter the territory on charges of trespassing on a military base and to detain them until they are turned over to CBP. At sea, Coast Guard cutters have been dispatched to monitor common migrant routes in the Florida waters and in the Gulf of Mexico (since renamed the Gulf of America by the administration) and in the Pacific between the United States and Mexico.
This show of force, coming alongside a highly publicized arrest and deportations initiative that has seen showy enforcement operations in U.S. cities and unauthorized immigrants flown to a high-security prison in El Salvador and put on military planes to India and other destinations, is undoubtedly acting as a further deterrent to would-be irregular border crossers. Indeed, some would-be migrants who had been waiting in Mexico for a hoped entry into the United States have begun making the dangerous journey in reverse, retracing their steps though the Darien Gap en route to their home country or other destinations in South America.
Finding the Formula for Sustained Lows
The Trump administration is also using fundamentally different tactics in engaging with the region. Under President Joe Biden, the U.S. government promoted the Los Angeles Declaration on Migration and Protection, a regional dialogue that called for cooperation and regional management within the hemisphere to curtail mass migration. Though it may not be the formula, the declaration offered building blocks for a well-managed migration system in the region stretching from Chile to Canada. In contrast, the Trump administration has threatened tariffs unless countries such as Mexico and Canada increase migration controls and others, such as Panama and Costa Rica, agree to accept third-country nationals deported by the United States.
The quiet border has led Homeland Security Secretary Kristi Noem to declare that the administration “has almost 100% operational control of the border,” which the Department of Homeland Security (DHS) now defines as getting Border Patrol agents back into the field rather than processing migrants. The first Trump term itself offers some evidence, though, that successes at the border cannot be sustained over time.
The early months of the first Trump term saw directives to build a border wall, increase detention capacity, and end “catch and release” (the term used to describe the release into the U.S. interior of those apprehended at the U.S.-Mexico border after processing). Coupled with strong anti-immigration rhetoric, the measures did initially cause irregular encounters to decrease (see Figure 3). However, within months of Trump taking office in 2017, border encounters were once again on the rise.
Figure 3. Irregular Migrant Encounters by U.S. Border Patrol at U.S.-Mexico Border, 2017–21
Note: The 2021 data are for January.
Source: Data for 2017-20 can be found at CBP, “U.S. Border Patrol Monthly Encounters (FY 2000-FY 2020),” accessed May 29, 2025. Data for 2021 can be found at CBP, “CBP Nationwide Encounters.”
In reaction to the increased border arrivals, the Trump administration in May 2018 implemented the zero tolerance policy that resulted in more than 5,000 children being separated from their parents by the U.S. government. In January 2019, it implemented the Migrant Protection Protocols (MPP, often known as Remain in Mexico), which required more than 80,000 would-be asylum seekers to wait in Mexico, in often difficult conditions, for the duration of their case.
While these policies caused brief decreases in border encounters, their impacts were not long-lasting. For example, following implementation of the zero tolerance policy, migrant encounters decreased for just two months before rising to levels higher than before the policy was put in place. And after the implementation of MPP, irregular encounters reached their highest level of the Trump administration. Even after the onset of the COVID-19 pandemic, which shut borders around the world, and the implementation of Title 42—a public health authority that allowed for immediate expulsions—irregular encounters dropped only briefly before rising once again (see Figure 3).
Refocusing on Border Management
Movements to the U.S.-Mexico border are dynamic and depend upon much more than U.S. policy. Changing economic situations, war, regional or global policy changes, and political upheaval are among the factors that can affect the ability of the U.S. government to respond to changing migration patterns.
Though encounter levels at the U.S.-Mexico border are near historic lows, history shows that migration never fully stops. Rather, it adjusts to changing environments. The narrowing of humanitarian pathways and increased enforcement, at U.S. borders and in the interior, may have reduced encounters for now. But it could also expand business for smugglers to facilitate covert entry, perhaps via tunnels under the border or maritime routes, or shift crossings to more remote areas that have been quiet over recent years.
Given that migrant crossings are affected by myriad variables outside of U.S. policy control, the focus ought to be on effectively managing the flow to the border rather than seeking to stop it in its tracks—an historically unreachable goal as demonstrated by regularly occurring spikes in irregular arrivals (see Figure 4), in administrations Democratic and Republican alike, despite a consistent trendline over the past nearly four decades of ever increasing resources and authorities at the border.
Figure 4. Irregular Migrant Encounters by U.S. Border Patrol at U.S.-Mexico Border, FY 1996–2025*
Note: These are encounters between ports of entry by U.S. Border Patrol. The fiscal 2025 data are through April.
Source: Data for fiscal year (FY) 1996-2019 can be found at CBP, “United States Border Patrol, Southwest Border Sectors, Total Illegal Alien Apprehensions by Fiscal year,” accessed June 6, 2025. Data for FY 2020-25 can be found at CBP, “Nationwide Encounters.”
Changing realities at the border, including litigation that could threaten the viability of some current border policies, will test the Trump administration’s ability to manage migration solely through a deterrence-focused approach. During the first Trump administration, such strategies resulted in short-term declines in encounters but did not provide for sustained lows. In unraveling key policies that contributed to establishing today’s quiet border, the administration is gambling with the possibility of increased irregular arrivals in the future.
U.S. Immigration Policy program