WASHINGTON, DC — The Migration Policy Institute (MPI) today released its newest estimates of the size and top countries of origin of the unauthorized immigrant population in the United States, estimating the number at 11.2 million in 2021. That figure is up from 11.0 million in 2019—a larger annual growth rate than seen since 2015. The estimates derive from MPI’s unique methodology, developed in concert with demographer Jennifer Van Hook at The Pennsylvania State University’s Population Research Institute, to assign legal status to foreign-born populations recorded in the U.S. Census Bureau’s American Community Survey (ACS), for which 2021 is the most recent year available.
While the U.S. public might expect an even greater jump in the size of the unauthorized immigrant population, it is important to note that these 2021 data do not capture the record number of border encounters witnessed in 2022 and the high levels seen this year. These mid-2021 estimates also reflect the population during a period when global mobility was still depressed due to the COVID-19 pandemic. And there is always population change, with people exiting the unauthorized immigrant population due to voluntary or forced departure from the United States, death or, in a narrow set of circumstances, access to legal permanent residence. MPI’s latest estimates reflect the growing diversification of the U.S. unauthorized population, due both to the decade-long decline in the size of the Mexican unauthorized immigrant population and the widening array of nationalities arriving at the U.S.-Mexico border from within and beyond this hemisphere. The diversification also stems from visa overstays by migrants from around the world. The Mexican unauthorized immigrant population, which stood at 5.2 million in mid-2021, had fallen about 32 percent from its 7.7 million peak just before the start of the 2008-09 Great Recession. In addition to voluntary and forced return and other factors driving this decrease, it is likely that more Mexican migrants were utilizing lawful pathways to come to the United States, including the H-2A visa for seasonal agricultural work, so fewer were migrating irregularly.
Declines in the Mexican unauthorized immigrant population for this period were offset by increases in irregular arrivals from other countries. The unauthorized immigrant populations from places such as Guatemala, Honduras, Venezuela and other parts of South America grew between 2019 and 2021, as did populations from the Caribbean and Africa, among others. Table 1. Top 10 Countries of Origin for Unauthorized Immigrants in the United States, 2021 
Source: Migration Policy Institute (MPI) estimates of the U.S. unauthorized immigrant population are developed in collaboration with Jennifer Van Hook of The Pennsylvania State University’s Population Research Institute by subtracting the number of legal immigrants from the total of all immigrants for each country and region represented in U.S. Census Bureau American Community Survey (ACS) data. The number of legal immigrants is estimated by adding up all legal admissions from each country and region in every year—using U.S. Department of Homeland Security (DHS) administrative data—and then reducing this number to account for deaths and emigration of legal immigrants. Finally, the unauthorized immigrant population estimates are adjusted upward slightly to account for the recognized undercount of this population in the ACS. For more detail on this methodology, see MPI, “MPI Methodology for Assigning Legal Status to Noncitizen Respondents in U.S. Census Bureau Survey Data.” Migrants from Latin America and the Caribbean accounted for 79 percent of all unauthorized immigrants in 2021. Table 2. Regions of Birth of Unauthorized Immigrants in the United States, 2021 
Source: MPI estimates, developed in collaboration with Van Hook. Future data will reveal how the size and origins of the unauthorized immigrant population have shifted during the very dynamic period of U.S.-Mexico border arrivals in 2022 and 2023. For a complete look at the new MPI estimates, click here. MPI will be updating its detailed profiles of unauthorized immigrant populations at U.S., state and top county levels, which currently feature 2019 data because the Census Bureau deemed that the 2020 ACS collected during the onset of the COVID-19 pandemic did not meet its quality standards. And for a more detailed discussion of MPI’s methodology to assign legal status in Census Bureau data, click here. | 
