A new report from the Center for Immigration Studies (CIS) reveals that President Trump’s crackdown on illegal immigration has had an “astonishing” impact on the illegal alien population in the United States, reducing the number of people in the country illegally by a reported 1.6 million in just six months, a historic shift that the researchers described as “unprecedented” for such a relatively short time period.
For background, on August 12, 2025, the Center for Immigration Studies (CIS), an organization that describes itself as “low-immigration” and “pro-immigrant,” released a report showing that the illegal immigrant population in the United States declined by 1.6 million (10 percent) from January to July 2025. The authors of the report concluded that the decrease has had a positive impact on job growth for American citizens.
In their report, CIS researchers Karen Zeigler and Steven Camarota concluded that President Trump’s immigration crackdown had dropped dramatically in “the largest six-month decline ever within the same year.” The researchers continued, “Non-citizens accounted for all of the falloff in the total foreign-born; the naturalized U.S. citizen population has actually increased some since January.”
Moreover, based on their findings, the researchers concluded that the mass exodus of illegal immigrants from the country may lead to “a tighter market and higher wages,” which, they deduced, “may help to draw back into jobs the near-record number of working-age American men without a college degree not in the labor force.”
Furthermore, the researchers advised policymakers to “consider these positive effects of reducing illegal immigration as they respond to pressure from employers to reverse the decline,” concluding that employment of U.S.-born individuals had risen by 2.46 million since January 2025, calling the “enormous change” definitive “good news.”
Additionally, based on the data, the researchers concluded that the sharp decline in the country’s illegal immigrant population has correlated with “significant job growth among the U.S.-born.” They continued, “While employers may be unhappy with a decline in illegal immigrant workers, reducing the supply of labor is likely to be very helpful to less-educated U.S.-born and legal-immigrant workers, whose wages may rise as a result.”
Importantly, the authors of the report also concluded that the sudden decrease in illegal immigration was directly correlated to the election of Donald Trump, his rhetoric, high-profile enforcement actions, and border policies,” which, they determined, “have caused a large number of illegal immigrants to leave the country and many fewer to enter.”
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However, the authors of the report presented “a few important caveats” that may have affected their data, stating, “Given recent stepped-up enforcement efforts, it is possible that the observed decline in the foreign-born was due, at least in part, to a greater reluctance by immigrants to participate in the survey or to identify as foreign-born.” The researchers added that some data for July 2025 was not yet available at the time the report was published.
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