The illegal alien population in the United States recently hit a record high in the wake of the Biden administration’s border policies and now sits at a whopping 18.6 million, a recent study found.
The study from the Federation for American Immigration Reform (FAIR) found that the number of illegal aliens present in the United States has surged 11 percent since June 2023, when the estimate sat at 16.8 million. The figure sits a full 28.2 percent higher than in December 2020, the month before former President Joe Biden took office.
Under FAIR’s new estimate, the illegal alien population present in the country is believed to be greater than the populations of all but the four most populous states in the union. “As of 2025, American population growth comes almost entirely from unsustainably high levels of immigration, both legal and illegal,” FAIR wrote.
From The Federation for American Immigration Reform
FAIR, which advocates for border security and a reduction in legal immigration, asserts that the increased illegal alien population was due largely to “pull factors” resulting from the Biden administration’s border policies.
“In its first few months in power, the Biden administration sent a strong message of welcome to would-be illegal aliens,” FAIR writes, citing the former White House’s decisions to halt border wall construction, expand the grounds for claiming asylum, and rescind Asylum Cooperative Agreements, further expanding the pool of migrants who could apply for asylum.
“These policies had the expected effect,” FAIR charges. “Illegal border crossings began to rise as soon as the Biden administration took office, and they continued growing to catastrophic levels throughout the administration’s term.”
The organization also noted the challenges that come when attempting to estimate the illegal population, while also contending that other estimates significantly undercount the true figure. “Estimating the size, distribution, and characteristics of the illegal alien population is an inexact science,” FAIR points out. “We do not know exactly how many people cross the border illegally and evade immigration authorities, nor can anyone accurately quantify overstays or gotaways.”
“The Department of Homeland Security only (loosely) counts foreign nationals who enter and leave the United States in a lawful manner,” FAIR noted, adding that “its illegal alien population estimates remain unhelpful due to underestimating the size of the population and utilizing outdated numbers.”
FAIR’s estimate comes a year after the Center for Immigration Studies (CIS) found that the foreign-born population in the United States reached a new high of 51.6 million in March 2024. The increase under the Biden administration, CIS estimated, was due primarily to mass illegal immigration.
Border crossings have plummeted to record lows under President Donald Trump, whose administration has carried out waves of deportation operations. Other policies could encourage illegal aliens to leave the United States on their own.
Congress could require businesses across the country to use the E-Verify system to confirm the legal status of would-be employees and prevent illegal aliens from acquiring jobs. Border Czar Tom Homan celebrated the program in 2020, saying that it “is the best tool available, and currently prevents a significant amount of unauthorized employment.”
