The U.S. Unauthorized Immigrant Population Reaches New Levels and Diversifies, MPI Estimates Show

WASHINGTON, DC — The Migration Policy Institute (MPI) today released its latest estimates of the size of the unauthorized immigrant population in the United States, pegging the number at 15.8 million in mid-2024, after hovering in the 11 million range throughout the decade beginning in 2010. 

The increase is primarily driven by record unauthorized arrivals at the U.S.-Mexico border and the Biden administration’s wide use of humanitarian parole programs to reduce chaos at the border. As a result of these grants of parole and other Biden administration moves, MPI estimates that, as of mid-2024, a maximum of 40 percent of unauthorized immigrants in the United States held a liminal (or “twilight”) status providing them temporary protection from deportation, such as Temporary Protected Status (TPS), Deferred Action for Childhood Arrivals (DACA), humanitarian parole or pending asylum application.

The MPI estimates, developed in concert with Jennifer Van Hook, a demographer at The Pennsylvania State University’s Population Research Institute, derive from a residual method that subtracts estimates of the legally resident foreign born from the total immigrant population recorded in the U.S. Census Bureau’s American Community Survey (ACS). The most recent ACS is for 2024.

The estimates reflect the growing diversification of the U.S. unauthorized immigrant population, due to the widening array of nationalities arriving at the U.S.-Mexico border over the past several years from within and beyond this hemisphere. The Mexican share of the unauthorized immigrant population was 35 percent as of 2024—a sharp decline from the 62 percent share in 2010 and 49 percent in 2019. 

Table 1. Unauthorized Immigrants in the United States from Mexico and by Region, 2019 and 2024

Between 2019 and 2024, the unauthorized immigrant population from Central America increased by 2.3 million, a change driven primarily by migration from Honduras and Guatemala. The South American population increased by 1.3 million over the same period, primarily due to large-scale migration from Venezuela, Colombia, Ecuador and Brazil. 

Table 2. Top Ten Countries of Origin for the U.S. Unauthorized Immigrant Population, 2019 and 2024

Among other findings:

• While the unauthorized immigrant population experienced a net increase of 394,000 over the decade between 2010 and 2019, it had net growth of approximately 5 million people between 2019 and 2024, or an average of 8 percent per year. The increases were driven by a range of factors including the uncommonly strong U.S. economic recovery after the COVID-19 pandemic and large-scale displacement from countries throughout the Americas. 
• In 2024, up to 40 percent of those counted in the MPI estimates held some kind of temporary legal protection offering them short-term relief from deportation and access to work authorization. This estimate is likely an overcount, as it does not adjust for an unknown number of people who hold more than one kind of temporary status. Many have subsequently lost their status, though, given Trump administration actions to terminate TPS programs, rescind humanitarian parole status from several groups and deny certain asylum applications.

Analysts Ariel G. Ruiz Soto, Julia Gelatt and Van Hook note that the unauthorized immigrant population is likely to have stayed relatively constant or decreased  in 2025 and beyond, given the quieter U.S.-Mexico border inherited by the Trump administration as well as the stepped-up immigration enforcement being seen across U.S. communities.

“Should the administration succeed in its efforts to sizably ramp up deportations and if border entries remain at their remarkably low levels, the unauthorized immigrant population may begin to decrease into 2026 and beyond,” they write.

For a complete look at the new estimates, visit: www.migrationpolicy.org/commentary/us-unauthorized-immigrant-population-new-peak.

MPI will next be updating its detailed profiles of unauthorized immigrant populations at U.S., state and top county levels.