The United States’s illegal immigrant population soared to an all-time high of 14 million people in 2023 as millions of people illegally crossed into the country from Mexico during the Biden administration’s border crisis, according to a new report.
The Washington-based Pew Research Center revealed on Thursday that the number of illegal immigrants in the country rose by 3.5 million people by 2023 and continued to go higher during former President Joe Biden’s final year in office.
“In the years after the COVID-19 pandemic, U.S.immigration policy changes fueled a sharp rise in both legal and illegal immigration,” Pew stated in its report. “Lawful admissions jumped, as did encounters at the U.S.-Mexico border between migrants and U.S. authorities.”
At the start of Biden’s term, roughly 10.5 million illegal immigrants resided in the U.S. All data, including that from 2023 and years past, was based on an analysis of Census Bureau data from the American Community Survey.
The Biden-era border crisis saw more than 10 million people illegally enter the country from Mexico in four years, the majority of whom were permitted to remain. Additionally, hundreds of thousands more people were temporarily paroled into the U.S. from abroad under a program that the Biden administration created.
As illegal entries at the border continued through 2023 and into 2024, the total number of illegal immigrants in the U.S. also grew.
“Growth slowed considerably in the last half of 2024 after the Biden administration stopped accepting asylum applications at the border and paused parole programs,” the Pew report stated. “In 2025, the unauthorized immigrant population has probably started to decline, due in part to increased deportations and reduced protections under the Trump administration.”
The report states that, based on data from a current population survey, the overall immigrant population in the United States declined by more than 1 million between January and June 2025. It’s unclear how much of that figure is from illegal immigrants leaving the country.
The Trump administration has claimed that 1 million illegal immigrants have chosen to self-deport. Still, as of mid-2025, the illegal immigrant population is believed to be higher than the 2023 figure.
Nationalities of illegal immigrants
Mexico has historically been the top nationality of illegal immigrants in the U.S., but as of 2023, it only accounted for 30%, down from more than 50% in 2016.
That decline coincides with the dramatic increase in Central American migrants who traveled across the southern border to the U.S. during the Obama, Trump, and Biden administrations.
Central American countries Guatemala, El Salvador, and Honduras all had between 775,000 and 850,000 citizens illegally residing in the U.S., followed by 680,000 people from India and 650,000 from Venezuela.
States with the highest populations
Democrat-run states made up four-in-six of the states with the largest populations of illegal immigrants. California led with 2.3 million illegal immigrants, followed by Republican strongholds Texas and Florida, then New York, New Jersey, and Illinois.
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The six states have historically had the highest number of illegal immigrants since 1980, according to Pew.
Florida’s illegal immigrant population grew the fastest from 2021, the start of the Biden administration, to 2023.