The United States endured a never-before-seen surge in illegal immigration under President Joe Biden, watching as hordes of migrants charged border barriers and towns across the country were reshaped virtually overnight by mass migration.
The issue, perhaps more than any other, propelled President Donald Trump to victory in the 2024 election. Trump pledged to end the “invasion on our southern border” throughout his campaign. And in the first 100 days of his second administration, the president has slashed border crossings to a fraction of what they were just months ago.
Through a combination of policy changes, arrests and deportations, sanctions, and coordination with foreign governments, Trump says his administration has facilitated a dramatic 99.9 percent drop in border encounters.
Customs and Border Protection data recorded over 11 million illegal alien encounters nationwide under the Biden administration — roughly 9 million of which took place at the southern border. By May of Biden’s last year in office, federal data showed that 1.7 million illegal alien “gotaways” entered the country.
Illegal immigration was so dramatic under Biden that the foreign-born population surged to a new high of 53 million. Two-thirds of the growth of the foreign-born population during the Biden presidency is estimated to be due to illegal immigration. There are approximately 18.6 million illegal aliens currently present in the United States, according to the Federation for American Immigration Reform.
But the situation on the southern border changed drastically after Trump’s inauguration.
“From Jan. 21 through Jan. 31, the number of U.S. Border Patrol apprehensions along the southwest border dropped 85% from the same period in 2024,” the White House pointed out in a press release, citing ABC News.
The Trump administration recorded a 93 percent drop in illegal border crossings in the eleven days after Trump’s inauguration. The decline proved to be even more precipitous by March, when Vice President JD Vance visited the southern border and boasted of a 98 percent reduction in border crossings.
The rapid drop in border crossings came after Trump announced and implemented sweeping changes to immigration policy. Upon taking office, Trump declared a national emergency at the southern border, ordering the Secretary of Defense to deploy troops to the border and for border wall construction to resume.
By early March, roughly 9,000 active-duty soldiers were at the southern border.
One of Trump’s most consequential policy changes was the reinstatement of the Remain in Mexico policy, which requires migrants to stay in Mexico while their asylum claims are processed.
It’s a departure from the Biden administration’s catch-and-release policy, which allowed asylum seekers to enter the United States and live and work in the country while their claims are processed. Some migrants freed into the country under Biden were given court dates in 2035.
Trump also immediately suspended the Refugee Admissions Program and halted flights of migrants from Cuba, Haiti, Venezuela, Nicaragua, El Salvador, Guatemala, Honduras, Colombia, and Ecuador, which the Biden administration used to streamline more than 300,000 migrants into the interior of the United States.
In March, the Trump administration repurposed an online application that the Biden administration used to bring hundreds of thousands of migrants into the interior of the country. Formerly called CBP One, the Biden administration used the app to let migrants remotely schedule asylum appointments. It has since been renamed CBP Home, and allows migrants to alert the government of their “intent to depart” the United States.
Trump’s Department of Homeland Security even launched an international advertising campaign warning would-be illegal aliens not to attempt to enter the United States.
“If you are a criminal alien considering entering America illegally: Don’t even think about it. If you come here and break our laws, we will hunt you down. Criminals are not welcome in the United States,” Homeland Security Secretary Kristi Noem says in the ads, which have been broadcast on television, radio, social media, and even through targeted text messages.
The effects of Trump’s immigration policies weren’t just seen at the southern border. They’ve even been noticed by Latin American countries like Colombia, which watched as caravans of migrants traveled through it on their way to the United States.
Colombia recorded a 61 percent decline in migratory flow through the country to the Darién Gap, a treacherous stretch of jungle that migrants cross through on their way to the United States in the first month of Trump’s administration. Colombia attributed the decline to “the change in U.S. immigration policy” under Trump.
