The U.S. foreign-born population fell by 2.2 million in the first half of 2025, with 1.6 million of the decline coming from the illegal-immigrant cohort, according to a Center for Immigration Studies analysis of the Census Bureau’s monthly Current Population Survey. CIS estimates the unauthorized population now stands at about 14.2 million, reversing roughly one-third of the increase recorded during the Biden administration. Researchers calculate the illegal-immigrant population has been shrinking by nearly 270,000 a month since January, the steepest contraction on record. The findings coincide with an aggressive enforcement campaign by President Donald Trump’s administration. Homeland Security Secretary Kristi Noem said July border encounters fell to 24,630—another record low—and the department has completed a third straight month without releasing any migrants into the country after apprehension. CBP data show only 4,601 arrests along the southwest border in July, down 92 percent from a year earlier. Interior enforcement has also intensified. Immigration and Customs Enforcement’s Houston field office reported 356 arrests of criminal gang members during the first six months of the year, a 375 percent increase compared with the same period of the previous administration. Nearly 70 percent of the more than 300,000 nationwide arrests touted by the White House involve non-citizens with prior convictions, according to administration figures. CIS research director Steven Camarota said the sharp outflow could ease pressure on public services and tighten labor markets, while Noem noted foreign governments are seeing “hundreds of thousands” of their citizens return home voluntarily. The census-based estimates have not been independently audited, but they mark the largest six-month drop in the nation’s foreign-born population since records began.