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What are the latest estimates of the undocumented immigrant population in the U.S. (2024–2025)?
Executive summary
Different organizations give widely different counts for the U.S. undocumented/unauthorized population for 2023–2025: mainstream academic estimates cluster around 10.5–14 million (Pew: 14 million in 2023; CMS/MPI: ~11–11.7 million), while advocacy and enforcement-oriented groups produce higher or lower figures (FAIR: 18.6 million in March 2025; CIS/CBO-derived analyses produce other higher provisional counts). Pew says the unauthorized population rose from about 10.5 million in 2021 to 14 million in 2023 and likely peaked in 2024 before starting to fall in 2025 [1] [2] [3] [4] [5].
1. Why estimates diverge: methods, definitions and timing
Different estimates use different methods (residual estimation from surveys, adjusted Census/ACS weights, CPS-based provisional counts, operational tallies of encounters, or administrative records), and they define the population differently (unauthorized only vs. broader “illegal aliens” or including parolees and liminal statuses), so numbers are not directly comparable; for example, Pew’s 14 million figure for 2023 comes from ACS-based residual methods adjusted for new Census migration estimates [1] [2], MPI and CMS produce lower 2022/2023-era estimates around 11.0–11.7 million using residual and CPS adjustments [6] [4], while FAIR’s 18.6 million (March 2025) is a higher estimate based on different assumptions [5]. Migration Policy Institute and CMS explicitly note methodological limits and revisions when incorporating new Census Bureau population estimates [6] [4].
2. The mainstream academic consensus (rough bounds and recent upward trend)
Established demographers and research centers before late-2024 reported figures roughly between 10.5 million and 11.8 million for 2021–2022 (Pew/ CMS/ MPI/Robert Warren) and then documented a sharp rise into 2023: Pew reports 14 million in 2023, representing a 3.5 million increase since 2021 and calls 2021–23 the largest two‑year rise in their series [2] [1]. CMS’s provisional CPS-based work reported 11.7 million in July 2023 and Robert Warren documented an increase of roughly 650,000 in 2022 [4] [7]. Authors stress that 2023–24 were highly dynamic and that 2024–25 trends remain provisional given data lags [2] [1].
3. Evidence on 2024–2025: growth, pause, and then probable decline
Pew and MPI analysts say the surge continued into early 2024 but growth slowed after mid-2024 because of policy changes (restrictions on asylum, pauses in parole) and increased removals; Pew notes the unauthorized population likely peaked in 2024 and “probably started to decline” in 2025 partly due to higher removals and reduced protections [1] [2]. Other data points support falling border encounters in 2025—CBP reported dramatic year‑over‑year declines in monthly encounters by mid‑2025 [8]. DHS statements and FAIR’s later higher totals present a different picture: FAIR claims 18.6 million in March 2025 and DHS/administration releases assert large numbers removed or self‑deported in 2025, which, if accurate, imply rapid change in the population but rely on administrative tallies and policy claims rather than the survey‑adjusted demographic methods used by Pew/MPI/CMS [5] [9] [10].
4. What counts as “undocumented” or “unauthorized”: contested inclusions
Some organizations include parolees, temporary parole program entrants (e.g., CHNV, Uniting for Ukraine), and certain humanitarian categories in their tallies or in related analysis; Pew notes that some parole admissions were incorporated into Census adjustments for 2021–2023 and that inclusion decisions affect totals [2] [11]. MPI and Migration Policy’s state profiles use an imputation approach that may include liminal statuses [12]. FAIR and CIS use different constructs and CPS reweighting approaches that produce much higher or different mid‑2024/2025 estimates [5] [13].
5. How to interpret the large spread: practical guidance
Use the estimates for the purpose you need and cite the method: for demographic, labor‑market or long‑term trend analysis, rely on peer‑reviewed or Census/ACS‑based residual estimates (Pew, MPI, CMS) and note revisions; for near‑real‑time operational counts, use CBP/DHS encounter statistics and DHS removal tallies but understand they do not equal net population change without demographic adjustment [2] [4] [8] [9]. Independent observers like PolitiFact note the credible range across institutions commonly spans roughly 10.9–16.8 million historically, illustrating uncertainty and methodological sensitivity [14].
6. Bottom line and limits of available reporting
Available sources show mainstream demographers put the unauthorized population in the low‑to‑mid‑millions with Pew’s revised ACS‑based estimate peaking at 14 million in 2023 and CMS/MPI figures near 11–11.7 million for the same period; trends through 2024–25 are disputed—Pew and MPI note a mid‑2024 slowdown and likely 2025 decline, while FAIR and some CPS‑reweighting analyses report higher March‑2025 totals [1] [2] [4] [6] [5]. Complete, definitive 2024–2025 demographic estimates remain pending because major sources warn that administrative and survey data remain incomplete and subject to revision [2] [1].