Number of illegal immigrants in USA
Executive summary
Current expert estimates for the number of unauthorized (commonly labeled “illegal”) immigrants living in the United States cluster between about 11 million and 14 million, with alternative methods producing higher figures—some advocacy or academic models place the number as high as roughly 18–22 million—because measurement depends heavily on methodology and recent migration flows [1] [2] [3] [4] [5].
1. What the leading, peer-reviewed and government-linked estimates say
Major research centers and government-adjacent inventories converge around a mid-teens figure: Pew Research Center incorporated revised Census migration inputs and estimated a record 14 million unauthorized immigrants in 2023 (their updated series through 2023) [2] [6], the Center for Migration Studies and others produced estimates around 12.2 million for 2023 [3], and Migration Policy Institute/Immigration Research Initiative summaries report three commonly cited estimates that round to about 11 million at the national level [1].
2. Why estimates differ: methodology matters
Different counts spring from distinct methods—residual survey subtraction (using ACS/Census to infer the unauthorized by subtracting legally recorded foreign-born), administrative-operational models that blend deportations, overstays and demographic modeling (which produced Yale’s 22.1 million estimate), and real-time agency tallies that can undercount or double-count removals; those methodological choices produce divergent totals and explain why researchers like Pew, CMS, MPI, Yale and advocacy groups arrive at different numbers [7] [5] [3] [1] [2].
3. The role of recent migration flows and policy in changing the count
Recent years’ migration dynamics have shifted estimates: new Census Bureau population corrections for 2021–2023 raised migration measures and helped push Pew’s 2023 estimate to 14 million [2], while policy changes—parole policies, revocations of temporary protections, and increased removals projected in CBO scenarios—affect both the actual unauthorized population and how researchers model departures and net flows [2] [8].
4. Outliers and politically motivated figures
Some organizations publish much higher or lower totals tied to advocacy aims: FAIR reported an 18.6 million figure in 2025 as part of its policy messaging [4], while academic papers using alternate demographic-operational modeling have claimed roughly 22 million undocumented residents—estimates that have attracted scrutiny and debate about assumptions and data inputs [5]. These outlier numbers often reflect implicit agendas—either to emphasize scale for policy restriction or to argue for more expansive legalization—so readers should weigh methodology as well as motive [4] [5].
5. What government sources provide and their limits
DHS and Office of Homeland Security Statistics publish time-series estimates and operational metrics (detentions, removals) that inform but do not directly settle a single national count; DHS tabulations and the CBO’s demographic projections illustrate how enforcement and policy can change the population trajectory, but they rely on assumptions about removals, voluntary departures, and future enforcement that make them projections rather than definitive headcounts [9] [8].
6. Bottom line: a defensible range and the uncertainty around it
The most defensible, widely cited range for the unauthorized population in recent peer-reviewed and center estimates is roughly 11–14 million in the early 2020s, with Pew’s updated series pointing to 14 million in 2023; alternative methods produce higher totals (roughly 18–22 million) but those are less consensual and rest on different, sometimes contested, assumptions [1] [2] [3] [4] [5]. Because surveys undercount and the policy environment is volatile, any single number should be treated as an estimate with clear methodological caveats rather than a precise census [7] [2].