New estimates put the U.S. undocumented immigrant population in mid-2024 at 14.6 million to 15.8 million, a sharp increase from around 11 million in the 2010s.

Since then the non-citizen population has likely dropped, but the number is unclear since immigrants facing hostility are reluctant to cooperate with government surveys.

The spike in the number of people living in the United States without documentation included between 5.4 million and 6.3 million people with some protection against deportation, such as humanitarian parole or temporary protected status.

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The Migration Policy Institute, which pegged the 2024 number at 15.8 million, said in a report released Wednesday that the increase was “primarily driven by record unauthorized migrant arrivals at the U.S.-Mexico border and the Biden administration’s wide use of humanitarian parole programs to reduce chaos at the border.”

Another group, The Center for Migration Studies of New York, estimated the undocumented population at 14.6 million for 2024. Both reports said they have proprietary methods of adjusting U.S. Census Bureau data and other data to make the estimates.

In the estimate from the Center for Migration Studies, California had the largest undocumented population at 2.6 million, followed by Texas (2.3 million), Florida (1.4 million), New York (920,000), New Jersey (703,000), Illinois (583,000), Georgia (502,000), North Carolina (460,000), Washington state (367,000) and Virginia (342,000).

Neither group had estimates from beyond 2024, though one monthly federal survey, the Current Population Survey, shows almost 3 million fewer non-citizens in June 2026 than there were in January 2025 at the start of the Trump administration. Non-citizens could be legal immigrants on visas or awaiting citizenship, as well as undocumented immigrants.

The U.S. Department of Homeland Security claimed in December that 2.5 million “illegal aliens” had left the country during the Trump administration, including through deportations and voluntary departures.

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The Center for Migration Studies in January called the DHS claim a “self-serving fantasy” based on a “flawed analysis of the Census Bureau’s monthly Current Population Survey.” Most likely the lower numbers in the survey reflect an unwillingness by immigrants to cooperate with surveys like the Current Population Survey, the January report said.

“Large numbers of immigrants targeted by ICE (Immigration and Customs Enforcement) and CBP (U.S. Customs and Border Protection) are now hunkering down in fear and are unlikely to provide any information about themselves to any strangers, especially government interviewers,” the report said.