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Fact check: How many illegal immigrants came into the U.S. under the Biden presidency?
Executive Summary
The available materials present divergent metrics but converge on one clear finding: encounters and reported illegal border crossings under the Biden administration number in the millions, not hundreds of thousands, and several sources place cumulative encounters since FY2021 above 10 million. Published counts vary by definition — “encounters,” “encounters at the Southwest border,” “new residents,” and modeled estimates of net additional unauthorized residents — producing headline totals that range from roughly 6.7 million additional residents to roughly 14 million cumulative illegal crossers through 2024 and beyond, depending on methodology and cutoff dates [1] [2] [3].
1. Numbers That Grab Headlines — Why “10 million” and “14 million” Both Appear in Reporting
Different public reports use different operational definitions: CBP encounter tallies count each interdiction or apprehension event, House Committee and CBP releases report nationwide encounters since FY2021 above 10.8 million, and some media and advocacy analyses aggregate cumulative illegal border crossers through FY2024 near 14 million. These figures are not mutually exclusive but reflect distinct counting choices: encounters can include multiple contacts with the same person, releases, expulsions, and non-Southwest border events, while administrative tallies may extrapolate to estimate residents [3] [1]. The reporting also differentiates fiscal-year snapshots — for example, nearly 3 million in FY2024 alone — versus multi‑year totals since January 2021, producing large but methodologically varied headline numbers [1] [3].
2. Official Border Patrol/CBP Operational Counts — What the Agencies Reported
CBP and related committee releases emphasize operational “encounters” as the primary hard data point. Multiple releases state that since FY2021 there have been more than 10.8 million encounters nationwide, including more than 8.7 million at the Southwest border, and nearly 3 million inadmissible encounters in FY2024 alone; these are agency-managed tallies based on border interdictions, expulsions, and apprehensions [3] [1]. CBP monthly updates also show steep month-to-month changes — for instance, reductions in crossings in late 2024 and a reported zero releases into the interior in May 2025 compared with tens of thousands a year earlier — underscoring rapid operational shifts as policies and enforcement resources change [4] [5].
3. Academic and Policy Estimates — From Encounters to Residents
Analysts and think tanks attempt to translate encounters into the estimated number of new unauthorized residents, producing different results. One model produced an estimate that 6.7 million new illegal migrants entered and established residence since 2021, projecting future growth to 24 million unauthorized residents by 2029 under status quo assumptions; this approach converts encounter flows into net population change and incorporates assumptions about return migration, removal rates, and settlement [2]. These modeled totals are sensitive to assumptions; encounters alone do not equal net additions to the resident population, and differences in assumed repeat crossings, enforcement removals, and asylum outcomes lead to divergent resident estimates [2] [3].
4. Time Trends Matter — Recent Declines and Earlier Peaks
Several sources document a sharp decline in encounters during 2024 after earlier peaks: analyses note a roughly 77% decline in migrant encounters at the U.S.-Mexico border from December 2023 to August 2024 and reported year-end decreases in unlawful crossings, with CBP showing a 60% decrease in southwest border encounters from May to December 2024 [6] [5]. At the same time, fiscal-year aggregates remain large because prior monthly totals were very high; thus annual and cumulative totals can mask recent downward trends, which agencies highlight when assessing current policy impact and resource needs [6] [5].
5. Reconciling the Claims — What a Careful Reader Should Take Away
The discrepancies among claims arise from definitions (encounter vs. individual resident), timeframes (FY vs. calendar year), and data provenance (CBP operational counts vs. modeled demographic estimates). The most directly measured quantity — CBP encounters and apprehensions — exceeds 10.8 million since FY2021 according to multiple official and committee releases, while modeled estimates of net new unauthorized residents vary from roughly 6.7 million to higher figures aggregated by some outlets to about 14 million depending on inclusion rules and extrapolations [3] [2] [1]. Readers should demand clarity on what is being counted: an encounter, a unique individual, or an added resident, and note that recent data show declines in encounters even as cumulative totals remain historically large [5] [6].