How many illegal immigrants are in the US? There is no exact live count. Recent research puts the unauthorized immigrant population at 14.6 million to 15.8 million in 2024, depending on the study. A newer, explicitly preliminary CIS estimate puts it at 13.5 million in July 2026. These figures describe different dates and methods; they are not interchangeable measurements of today’s population.
Research checked November 2, 2026. The 2024 figures come from research by the Center for Migration Studies of New York (CMS) and the Migration Policy Institute (MPI). The July 2026 figure comes from a September 3 release issued by the Center for Immigration Studies (CIS). CMS and CIS are separate organizations.
This guide uses unauthorized as its main demographic term and explains what the studies include. It compares dated estimates, shows how researchers calculate them and separates resident populations from border encounters, annual arrivals and enforcement totals.
US unauthorized immigrant population: compare the estimate year first
A report published in 2026 may measure people living in the country two or three years earlier. Read both the reference period and publication date before choosing a number to quote.
| Research source | Population reference period | Estimate | Publication date | How to describe it |
|---|---|---|---|---|
| Center for Immigration Studies (CIS) | July 2026 | 13.5 million | September 3, 2026 release | Preliminary estimate using monthly household-survey evidence; not an official count |
| Migration Policy Institute (MPI) | Mid-2024 | 15.8 million | July 29, 2026 | ACS-based estimate with administrative data and undercount adjustments |
| Center for Migration Studies of New York (CMS) | 2024 | 14.6 million | July 16, 2026 journal publication | Research estimate using 2024 ACS data and the study’s classification method |
| Pew Research Center | July 2023 | 14.0 million | August 21, 2025 | Earlier benchmark; not a measurement of 2026 |
The 14.6–15.8 million span describes the two listed 2024 estimates. It is not a statistical confidence interval, an average of all research, or a suggested range for November 2026. Likewise, MPI’s mid-2024 figure and CIS’s January 2025 baseline happen to round to the same number; that does not make them the same observation.
For a report or school assignment, a useful citation states the institution, estimate and reference period together. “MPI estimated 15.8 million in mid-2024” is more informative than “there are 15.8 million now.”
How many undocumented immigrants are in the US in 2026?
The most recent reference period among the estimates above is July 2026. CIS’s September release calls its 13.5 million figure preliminary and bases its analysis on the monthly Current Population Survey (CPS). It estimates a decline from 15.8 million in January 2025. That is a change within CIS’s analysis, not a comparison with MPI’s 2024 estimate.
The release also acknowledges that some measured decline could reflect immigrants becoming less willing to answer the survey, while saying it found no clear evidence of that explanation. Treat the number as an attributed provisional estimate, rather than a verified headcount or a precise November total.
There is a methodological trade-off between more recent monthly data and a larger annual survey. In its 2025 explanation of estimation limits, Pew says the CPS has a much smaller sample and insufficient detail for a precise separate unauthorized-population estimate. That is a general limitation Pew identifies, not a direct review of CIS’s September 2026 publication.
For searches asking about 2025 or today, retain the same discipline: a January baseline, a July estimate and an annual reference year describe different time points. None of the figures reviewed here establishes exactly how many people are in this population on November 2, 2026.
What do unauthorized, undocumented and illegal immigrant mean in these studies?
These terms often lead readers to the same population research, but the operational definition matters more than the label. Someone can be included in a demographic estimate without having entered by an unauthorized border crossing or being unknown to the government.
MPI’s published methodology includes people who entered without authorization, overstayed a visa or otherwise violated admission terms. It also includes certain people with temporary protections or pending cases, such as TPS, DACA, humanitarian parole and pending asylum applications. This grouping reflects its research definition; it is not a legal ruling about every person counted.
A pending asylum application and a grant of asylum are different categories. So are permission to work, a temporary reprieve from removal, lawful permanent residence and citizenship. Do not interpret a broad population label as proof that each person lacks every document or every form of permission.
CMS makes the distinction explicit: its 2024 study includes 5.4 million people with “liminal” circumstances who were documented and known to the government. In a separate analysis, MPI describes up to 40% with temporary protection in mid-2024, warning that overlapping protections can make the summed figure too high. These estimates use different categories; do not add their totals together. See the CMS study and MPI release for their definitions.
The broader foreign-born population also contains naturalized US citizens and lawful residents. A noncitizen is not automatically unauthorized. Our US immigration pathways guide explains the different application and status categories, while our Green Card guide introduces lawful permanent residence.
Research population categories do not determine an individual’s benefits eligibility. For that separate question, see our guide to undocumented immigrants’ health coverage and care options, which explains federal restrictions and state-specific checks.
How are illegal immigrants counted? The residual method explained
Researchers estimate a population that cannot be read directly from one comprehensive register. The basic residual approach starts with the foreign-born population, estimates the legally resident portion and calculates the remainder, with adjustments for coverage and other errors.
The Social Security Bulletin’s 2025 review of residual estimation explains this demographic approach and examines its assumptions. It is a methodological review, not a new 2026 population count, and its authors’ conclusions are not necessarily the official views of the Social Security Administration.
- Establish the survey population. Use a specified Census Bureau survey and its reference period.
- Estimate the lawful resident population. Combine relevant immigration records and demographic assumptions, accounting for people who died or left the country.
- Calculate the residual. Separate the estimated lawful population from the relevant foreign-born total.
- Address missing coverage. Adjust for people the survey is likely to miss, using the study’s evidence and assumptions.
- Check consistency. Compare with other demographic evidence and explain uncertainty or revisions.
This is the conceptual sequence, not a calculator that can reproduce a published study from two headline numbers. Researchers must reconcile different data sources, years, definitions and adjustments. Subtracting a visa-issuance total from a Census population figure does not reproduce the method.
Survey-based classification is also different from checking a named person’s documents. Population estimates support demographic analysis; they should not be used to infer a neighbor’s immigration status from appearance, language, address or national origin.
Why do credible immigration population estimates differ?
Start with three questions: Are the reference dates the same? Are the included groups the same? Are the data and adjustments the same? A difference can arise at any of these steps without either publisher claiming an exact census.
When using population figures to discuss taxes or public costs, read our guide to undocumented immigration’s US economic impact. It explains why population definitions and reference years must match the economic study, and why gross tax payments cannot be treated as a complete net fiscal balance.
Undercount matters because a household survey can miss residents. The size of the adjustment depends on the evidence and method used. A newer release may also revise older estimates when better population benchmarks become available.
For example, MPI’s July 2026 publication revises its estimate for mid-2023 to 14.7 million after updating its approach to recent-arrival undercount. That replaces its previous estimate for that period. The publication’s measurement notes explain the revision.
This has a practical consequence for any “by year” comparison: use a consistent series and edition. Do not draw a line from an older CMS estimate to a newer MPI figure and label the difference annual growth. Record revisions as well as new years, and retain the source notes when sharing a chart.
Undocumented immigrants versus border encounters: stock and flow
A population stock estimates how many people live in the country at a particular time. A flow measures events or changes over an interval. Border encounters, arrivals, removals and visa overstays answer different questions from the resident population total.
| Statistic | What it describes | Why it cannot replace the population estimate |
|---|---|---|
| Unauthorized resident population | People estimated to be living in the US at a reference date | Requires a population-estimation method |
| Border encounters | Recorded enforcement events over a period | Events are not a count of everyone who remains resident; repeat encounters can involve the same person |
| Annual entries or visa overstays | Part of the movement into an immigration category | Does not include all exits or changes of status |
| Removals or voluntary departures | Part of the movement out | Does not establish the starting population or all other changes |
For the repeated-event distinction, see Pew’s explanation of border encounters: the same person may be encountered more than once.
Pew explicitly warns that adding Border Patrol release or parole figures to an earlier estimate produces inaccurate totals. People can also leave, die or obtain a different status. Some arrivals are not represented by the particular border statistic being used.
The same accounting problem applies in reverse. Subtracting a publicized departure number from a historical estimate is not enough to establish today’s stock. The periods and definitions must align, and the calculation must account for other additions, exits and status changes.
When reading an immigration headline, first identify whether the number is people, events or cases. Our immigration news verification guide provides a wider checklist for checking the original source and relevant dates.
What percentage of the US population is undocumented?
The denominator changes the answer. Pew’s estimate for July 2023 was 4.1% of the total US population, while the same group represented 27% of the foreign-born population. Those percentages come from its 2023 population report, published in 2025. They are not competing percentages of the same denominator, and neither is presented here as a 2026 share.
For any updated percentage, use a numerator and denominator covering compatible dates and population definitions. Avoid dividing a provisional monthly estimate by an unrelated annual total and reporting the result as an official statistic.
Which states have the most undocumented immigrants?
The CMS 2024 study identifies California, Texas and Florida as the largest concentrations. Its table gives the following shares of the national undocumented population:
| State | Share of the national undocumented population |
|---|---|
| California | 18.0% |
| Texas | 15.9% |
| Florida | 9.8% |
| New York | 6.3% |
| New Jersey | 4.8% |
| Illinois | 4.0% |
Source: CMS study, Population Trends section. These are 2024 distribution estimates, not a 2026 map. In particular, “California: 18.0%” does not mean 18% of California residents were undocumented. It means California contained that share of the national population estimated by CMS.
Absolute population, share of the national group and share of a state’s residents are three different rankings. Choose the measure that matches the question, and keep the state figures within the same source and reference year.
A practical checklist before quoting a population figure
Save these fields alongside any number you use. This makes the claim traceable even when a new estimate is released.
- Source: the actual research publisher, not only a repost or headline.
- Reference period: the year and, where supplied, month or mid-year date.
- Release date: when that version was published.
- Definition: the groups included and excluded.
- Method and status: the survey, adjustments and whether the figure is preliminary or revised.
- Unit and denominator: residents, events, cases or a percentage of a specified population.
For this review, the clearest answer preserves both kinds of evidence: dated 2024 research benchmarks and a separately labelled provisional 2026 estimate. Keep the qualification attached whenever the figure is copied into a headline, social post, table or presentation.
How to use an unauthorized-population estimate in a chart or article
When reporting how many illegal immigrants are in the US, attach the estimate to its source and reference period in the same sentence. The date you publish a chart is not the date the population was measured.
| Reporting problem | A more accurate approach |
|---|---|
| A headline labels an older estimate as today’s count | Write the research organization’s name and the population reference period next to the number. |
| A newer release revises an earlier year | Label the revision and compare years from the same methodological series where possible. |
| A monthly-survey projection is mixed with an annual estimate | Identify the projection as preliminary and explain the different survey and adjustment methods. |
| A border encounters chart is labelled resident population | Keep event counts and estimates of people living in the country in separate charts. |
For instance, MPI’s July 2026 release describes a mid-2024 estimate and revises its mid-2023 series. That publication date does not turn the estimate into a July 2026 population count. Save the source version and correction date when replacing a chart. These research definitions also do not determine an individual’s eligibility for health coverage or low-cost care.
Frequently asked questions
Is there an exact count of illegal immigrants in the US today?
No. The sources reviewed provide estimates for specified dates. CIS gives a preliminary 13.5 million for July 2026; that is not an exact count for November 2, 2026.
Why do some reports say 14 million?
Pew Research Center estimated 14 million unauthorized immigrants in July 2023 and published that research in August 2025. The figure needs its reference year; it is not a 2026 count.
Does the estimate include people who overstayed visas?
Yes. The research definitions discussed here include visa overstays as well as people who entered without authorization. The population is not limited to people recorded crossing the southern border.
Are asylum seekers counted as undocumented immigrants?
Some research estimates include people with pending asylum applications among temporary or liminal categories. A pending application is different from a grant of asylum. Check each study’s definition rather than assuming every asylum-related category is treated identically.
Can border encounters be added up to get the total population?
No. Encounters are events, not a count of residents. Population change also depends on other arrivals, departures, deaths and changes of immigration status. Adding encounter totals to an old estimate does not establish the current population.