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How many illegal aliens came into the US during the Biden administration?
Executive Summary
Since President Biden took office in January 2021, federal agencies and reporting bodies have recorded between roughly 10.8 million and 11+ million total immigration encounters, with Southwest border encounters accounting for the majority; estimates of actual people who entered the country illegally vary because encounters include repeat contacts, expulsions, inadmissibles, and “gotaways.” Official Border Patrol encounter tallies and independent population estimates point to a large rise in unauthorized population and millions of encounters, but they are different metrics — encounters are operational counts, while population estimates measure residing unauthorized immigrants [1] [2] [3]. This analysis explains the key claims, reconciles differing metrics, identifies data gaps like “gotaways” and releases, and compares viewpoints from government reporting and demography studies to show why a single definitive count of “illegal aliens who came into the US during the Biden administration” does not exist in the data [4] [5] [6].
1. Why the big numbers don’t mean one clear answer
Government encounter data aggregate apprehensions, inadmissible refusals, and expulsions, so the headline totals cited by some sources — for example, more than 10.8 million encounters since FY2021 — do not equate to unique individuals entering the country [1]. Encounters count each Border Patrol or CBP contact; an individual who crosses, is expelled, and tries again generates multiple encounters, and conversely many crossings are never detected, labeled as “gotaways,” or result in releases that are not tracked as final entries. Congressional and CBP reports explicitly note gotaways and releases as major unknowns; some advocacy and political accounts convert encounter aggregates into claims about “illegal aliens who came in,” which is an apples-to-oranges comparison unless adjusted with demographically rigorous methods [2] [6].
2. Government tallies: millions of encounters, but different categories
CBP and related Homeland Security briefings present encounters in three principal categories: Border Patrol apprehensions, Office of Field Operations inadmissibles, and Title 42 expulsions — combined nationwide to create the KHSM encounter metric [7] [6]. Fiscal-year reporting cited by Congress and CBP documents shows roughly 10.8 million total encounters since FY2021 and over 8.7 million at the Southwest border specifically, while FY2025 Border Patrol stops were reported lower by some accounts [1] [4]. These official tallies are the best operational counts but explicitly exclude a reliable count of people who entered and remained because of repeat events, administrative releases, or non-detection. The policy implication is that enforcement statistics alone cannot measure net unauthorized population change or unique entries without supplementary demographic analysis [8].
3. Demographic estimates: population growth tells a related but different story
Independent demographic research and government population estimates show the unauthorized resident population rose from about 10.5 million in 2021 to roughly 14 million in 2023, a record two-year increase according to the provided analyses, implying substantial net additions to the resident unauthorized population during the Biden years [3] [5]. That population figure captures people living in the U.S. without authorization, including those who may have arrived earlier but remained, those who obtained temporary protections, or people counted during the period who were not newly arrived. Population change combines inflows, outflows, status adjustments, and mortality; therefore it provides a different lens from encounter data and supports the conclusion that millions more unauthorized residents lived in the U.S. by 2023 than in 2021 [5].
4. Key uncertainties that prevent a single definitive count
Several measurable but unresolved items create uncertainty: “gotaways” (undetected entries), multiple re-encounters by the same person, releases with no clear enforcement outcome, and status adjustments [2] [1]. Congressional briefings and CBP admit these gaps; advocacy groups and some media convert encounter totals into claims about the number of people who entered, which overstates certainty unless adjusted. Additionally, demographic estimates rely on survey inference and administrative data and can lag or smooth short-term flows. The result is a legitimate range of metrics — millions of encounters and a multi-million increase in resident unauthorized population — but not a single, verifiable count of unique illegal entries during the Biden administration [2] [8].
5. Bottom line: what can be stated with confidence and what remains debated
Confident facts: CBP and congressional records document roughly 10.8–11+ million total encounters since FY2021, with the Southwest border comprising the majority, and demographic research reports the unauthorized resident population rose to about 14 million by 2023 [1] [3]. Unresolved: the precise number of unique unauthorized entries is not directly observable from these datasets because encounters and population estimates measure different phenomena and have known blind spots like gotaways and releases [4] [6]. Policymakers and analysts must therefore cite which metric they mean — encounters, expulsions, inadmissibles, or resident population changes — and avoid presenting any single figure as the definitive count of “illegal aliens who came into the US” without acknowledging these measurement limitations [2] [5].