The number of illegal immigrants in the United States has dropped by an estimated one million since Donald Trump began his second term as president in January 2025, according to two reports analyzing data from the Census Bureau’s Current Population Survey (CPS). Researchers at the Center for Immigration Studies (CIS) attributed this significant decrease to Trump’s tough-on-immigration policies, heightened enforcement, and the perception that undocumented immigrants would face deportation if they stayed.
In January, CIS estimated that there were approximately 15.8 million illegal immigrants in the U.S. By May, that number had fallen to 14.8 million. Analysts Steven A. Camarota and Karen Zeigler explained that much of this drop came from non-citizens who had arrived in the U.S. after 1980, especially from Latin America. Within this demographic, the number of immigrants declined by roughly 1.07 million.
Both reports noted that several factors contributed to this rapid decrease. Many undocumented immigrants appear to have “self-deported,” leaving voluntarily as Trump ramped up immigration raids and messaging. The White House also incentivized departures with policies allowing illegal immigrants to leave the country without legal consequences through the CBP Home app. Other measures included offering one-way commercial flights home and a $1,000 stipend upon returning to their native countries.
The broader data also showed an overall decline of 957,000 in the total foreign-born population between January and May 2025. This drop is one of the most significant four-month decreases in decades, and it coincides with the most aggressive border lockdowns and deportation campaigns in years. The decrease among illegal immigrants contrasts with a slight uptick in the number of naturalized citizens, which implies that most of the overall decline was driven by people leaving rather than by changes in legal immigration or naturalization.
Both reports acknowledged that the CPS survey cannot directly identify illegal immigrants. Researchers relied on subtracting the estimated number of legal immigrants from the total foreign-born population to approximate the illegal immigrant count. They also cautioned that some undocumented immigrants may have avoided participating in the survey entirely due to fear of enforcement.
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