How many undocumented immigrants were living in the U.S. in 2025 by DHS estimate?
Executive summary
The Department of Homeland Security (DHS) has published statements asserting that roughly 1.6 million people "have left" the United States in a short period in 2025 and later framed that number as part of a broader claim that about 2 million "illegal aliens" exited the country in under 250 days (DHS news releases) [1] [2]. Independent analysts and research centers provide very different population estimates for the unauthorized population in recent years — Pew put the unauthorized population at 14 million in 2023 (with trends into 2024–25 uncertain) and FAIR and some policy analysts produced higher figures (15.4–18.6 million in various 2025 estimates) [3] [4] [5].
1. DHS’s headline figure: 1.6 million “left” and 2 million total exits — what DHS said
DHS publicly celebrated a milestone claiming "Two million illegal aliens have left the United States in less than 250 days," including “an estimated 1.6 million who have voluntarily self-deported and more than 400,000 deportations” in its September 2025 release, and an earlier August 2025 DHS statement quoted Secretary Noem saying “1.6 MILLION illegal immigrants have left the United States population” in under 200 days [2] [1]. DHS spokespeople told news outlets that the 1.6 million number was sourced from U.S. Citizenship and Immigration Services administrative counts but did not fully disclose the calculation or how that maps to the stock of undocumented residents [6].
2. What that DHS number does — and does not — measure
DHS’s announcements describe flows (people counted as leaving, deported or self‑deported) over a short period, not a contemporaneous estimate of how many undocumented immigrants were living in the U.S. on a specific date [2] [1]. Available DHS statements and the cited news reporting show DHS used administrative exit/encounter data and related agency tallies to produce the "left" figure but did not publish a full methodological benchmark tying those flows to an updated stock estimate of the unauthorized population [6] [2]. Available sources do not mention a single DHS "undocumented population in 2025" number produced with the same methods as historical DHS stock estimates [6].
3. Independent and scholarly estimates of the unauthorized population in 2023–25
Research groups use survey-based residual methods or other approaches to estimate the stock of unauthorized immigrants. Pew Research Center updated its estimate to say the unauthorized population reached a record 14 million in 2023 and sketched trends into 2024–25 while warning that complete estimates for 2024–25 are not yet possible because data remain incomplete [3]. The Center for Immigration Studies and some analysts using the Current Population Survey produced preliminary higher CPS‑based counts (e.g., a CIS analysis suggesting 15.4 million in January 2025) [4]. The advocacy group FAIR produced a much higher estimate — about 18.6 million as of March 2025 — using its own methodology [5]. These estimates differ because methods, data sources and assumptions about undercounts, outmigration and legalizations vary [3] [7].
4. Why estimates diverge: methods, timing and agendas
Divergent results stem from three facts: different base datasets (ACS vs. CPS vs. administrative DHS counts), differing residual‑estimation assumptions (how many legal immigrants to subtract, how many unauthorized have left or died), and timing (flow spikes during 2021–24 make short‑term trends hard to capture) [7] [3] [4]. Some sources have clear policy agendas: CIS and FAIR promote tighter immigration controls and report higher counts; DHS’s press framing emphasizes removals and deterrence [8] [5] [2]. Those competing incentives should inform how readers weigh each figure [2] [5].
5. What a careful reader should take away
DHS’s public claim about 1.6 million people “leaving” is a flow count, not an official DHS stock estimate of how many undocumented immigrants were present in the U.S. on a date in 2025; DHS says it sourced the 1.6 million from USCIS administrative numbers but has not published a matching residual‑style stock estimate for 2025 in the same public way as prior OHSS estimates [6] [2] [9]. Independent research groups place the unauthorized population in very different ranges: Pew’s authoritative ACS‑based work shows 14 million in 2023 with incomplete data for 2024–25 [3]; other researchers and advocacy groups report 15.4 million to 18.6 million using alternate methods [4] [5]. Those differences matter: a claim that "X have left" does not by itself prove the total population fell by X.
6. How journalists and policymakers should report this
Reporters and officials must distinguish flows (deportations, self‑deportations, returns) from stocks (how many unauthorized residents are in the country at a point in time) and cite methodology. DHS’s flow numbers merit scrutiny and demand transparent methods; independent estimates should be reported with their data sources and assumptions noted [2] [3] [4]. For now, the best public benchmarks for the stock are Pew’s ACS‑based 14 million and the suite of 2025 preliminary estimates (CIS, FAIR, DHS statements) — all of which differ and reflect methodological and political differences [3] [4] [2] [5].
Limitations: available sources do not provide a single DHS‑published estimate of the unauthorized population living in the U.S. at a specific date in 2025 comparable to Pew’s 2023 stock estimate; instead DHS released flow tallies and agency statements described above [6] [2].