What is the estimated number of illegal immigrants living in the US as of 2025?
Executive summary
Most reputable demographic researchers place the unauthorized (illegal/undocumented) immigrant population of the United States in 2025 near the low-to-mid tens of millions, with the best current syntheses pointing to roughly 14 million as a central estimate while acknowledging significant uncertainty and methodological disagreement across sources [1][2]. Alternative estimates range lower (roughly 11–12 million in some Center for Migration Studies and related work) and much higher (up to the high teens in advocacy or restrictionist group tallies), so any single figure for 2025 must be framed as provisional and contested [3][4].
1. The mainstream consensus: roughly 14 million and rising into 2023, ambiguous in 2024–25
Pew Research Center’s widely cited analysis put the unauthorized population at about 14 million as of mid‑2023 and used that ACS baseline to trace trends into 2024 and 2025, concluding that the population likely grew through 2024 and then showed signs of decline in the first half of 2025 but that definitive 2025 totals cannot yet be produced from available data [1][5]. Migration Policy Institute and related academic updates cluster near the low‑to‑mid‑teens for 2023 (MPI cited figures like 12.2–13.7 million for various estimates of 2023), reinforcing the idea that 14 million is within the mainstream envelope even if methods differ [2][6].
2. Why estimates diverge: surveys, administrative records, and methodology disputes
Different research teams use different inputs and the “residual” method—comparing Census, ACS or CPS counts of foreign‑born residents to administrative totals of legal immigrants—plus adjustments for undercount and emigration; those technical choices drive much of the spread in 2025 figures and make year‑to‑year comparisons fraught [7]. The American Community Survey‑based estimates (used by Pew) are treated as the gold standard but lag by a year and require complex undercount adjustments, while the CPS and administrative encounter data can suggest faster short‑term movements but are less comparable across methodological changes that occurred in 2024–25 [1][5][8].
3. Outliers: much higher and much lower tallies, and who is making them
Advocacy and politically aligned organizations supply outlying counts: the Federation for American Immigration Reform (FAIR) produced a high estimate of about 18.6 million for March 2025, a figure that departs from academic centers primarily because of different assumptions about undercount and migration flows [4]. Conversely, some Center for Migration Studies and earlier CMS-derived work has reported lower mid‑teens or even near 11.7–12.2 million for July 2023 depending on methodology, illustrating that even respected institutions can diverge when adjusting for recent flows and survey limitations [3][2].
4. What the evidence supports for “as of 2025” and the practical bottom line
Given the preponderance of peer‑reviewed and academic institutional work coupled with the most recent ACS‑based public analyses, the most defensible statement for 2025 is that the unauthorized immigrant population is likely in the neighborhood of 14 million with plausible uncertainty spanning roughly 11–19 million depending on methodological choices; however, mainstream demographers and centers (Pew, MPI, CMS) cluster nearer to 12–14 million and treat higher FAIR and CIS CPS‑derived extremes as outliers that rely on different assumptions about undercounts [1][2][4][8]. Importantly, analysts emphasize that policy changes and enforcement actions in 2025 likely altered flows and encouraged departures—factors that make mid‑2025 totals more volatile and provisional [5][9][10].
5. The uncertainty that matters for policy and reporting
Numbers matter politically, but methodological transparency matters more: researchers warn that short‑term CPS fluctuations, administrative “encounters,” and enforcement removals do not translate cleanly into a single national headcount and that all 2025 figures should be presented as estimates with clear error margins and assumptions specified [11][7]. Where reporting cites precise, single‑number counts for 2025 without disclosing method or range, those characterizations should be treated skeptically because leading demographers still consider a mid‑teens estimate with measurable uncertainty the most credible portrayal [1][2].