Between 2021 and 2023, the number of unauthorized immigrants living in the United States grew from an estimated 10.5 million to 14 million, according to a new Pew Research Center report. That is the largest two-year increase in more than 30 years of our estimates. The 14 million figure is also a new high, though preliminary data shows the population likely continued to grow and peaked in 2024.
In this Q&A, we speak with Senior Demographer Jeffrey S. Passel about how the Center estimates the number of unauthorized immigrants in the U.S. The interview has been condensed and edited for clarity.
How does Pew Research Center define ‘unauthorized immigrants’?
Unauthorized immigrants are those who are not members of any of the groups the U.S. has approved for legal immigration: legal permanent residents, refugees, people granted asylum and legal temporary migrants (e.g., foreign students).
The term “unauthorized immigrants” combines immigrants whose status is impermanent, precarious or both. For example, many unauthorized immigrants entered the country illegally. Others entered legally with a work or tourist visa but stayed longer than allowed. And others entered the U.S. legally with a temporary, precarious status.
Though the term isn’t perfect, it’s been used for decades by researchers to estimate the size of this population and is generally preferred over terms like “undocumented immigrant” or “illegal immigrant.”
Why is it important to know how many unauthorized immigrants are in the country?
Unauthorized immigrants make up about 4% of the U.S. population. It’s important to have a sense of their number, who they are and what their roles are in the economy when government policies affect them. Our estimates help provide insight into these factors, as well as how their population size has changed over time, where they’re from, where they live in the U.S. and how long they’ve been here.
One example of what we can learn from these estimates is that many U.S. families include both unauthorized immigrants and U.S. citizens. About 12 million people who are U.S. citizens or legal immigrants live in households with at least one unauthorized immigrant.
How do unauthorized immigrants enter the country?
As mentioned earlier, unauthorized immigrants enter the country in different ways. For many years, there were two main categories of unauthorized immigrants:
- People who enter the U.S. illegally
- People who enter the U.S. legally but overstay their visa or otherwise violate the terms of their admission
Historically, the majority of unauthorized immigrants entered the country illegally. The share who had overstayed visas grew in the 2010s.
In recent years, a third, but smaller, category of unauthorized immigrants has emerged as the federal government has created new programs:
- People who enter the U.S. legally with temporary protection from deportation that the government can revoke if immigration policy shifts
This third group includes migrants from certain countries facing war, natural disasters or other crises, as well as individuals who are paroled or released at the U.S.-Mexico border. In 2023, about 2 million of the 14 million unauthorized immigrants living in the country had been admitted into the U.S. with precarious statuses.
Why is someone who was given permission to come to the United States or to live and work here considered an unauthorized immigrant?
In recent years, an increasing number of immigrants have had temporary statuses that protect them from deportation. They are grouped as unauthorized immigrants because their statuses can be revoked, sometimes quickly, by the president or Congress.
The Trump administration has revoked the protections of many unauthorized immigrants this year. More than 500,000 immigrants from Cuba, Haiti, Nicaragua and Venezuela who were paroled into the U.S. between October 2022 and November 2024 had their temporary protection removed and work permits invalidated in 2025. The administration also allowed Temporary Protected Status (TPS) program protections to expire for 350,000 Venezuelans and 350,000 Haitians.
How many immigrants had these protections in 2023?
In 2023, more than 40% of unauthorized immigrants had some protection from deportation – about 6 million of our estimated 14 million total. This figure is up significantly from 500,000 (or 4% of the total) in 2007 and 2.7 million in 2021.
Protected groups include:
- Asylum applicants (2.6 million in 2023)
- Immigrants who entered the U.S. legally after receiving parole (700,000)
- Victims of crimes or violence (700,000)
- Those with TPS (650,000)
- Enrollees in Deferred Action for Childhood Arrivals (DACA), a program for immigrants who were brought to the U.S. illegally as children (600,000)
- Migrants who the U.S. Border Patrol released into the U.S. (1.0 million)
How did you estimate the number of unauthorized immigrants in the United States?
Conceptually, our method for estimating the size of this population is fairly straightforward.
- Estimate the number of immigrants who are in the country legally.
- Use data from a national survey or census to estimate the total number of immigrants (legal and unauthorized) living in the country.
- Subtract the number of legal immigrants from the total.
Our methodology includes many more details and refinements, but the basic calculation comes from this simple relationship.
Data for the total immigrant population comes from national Census Bureau surveys that ask respondents where they were born. (They do not ask about immigration status.) These surveys have large samples and have been conducted for many years.
Annual data on the number of people admitted to the U.S. as legal permanent residents (also called LPRs or green card holders), refugees or people granted asylum is available mainly from the Department of Homeland Security. So counting this group is more straightforward than trying to count the number of unauthorized immigrants directly. We use the annual totals to estimate the current population of immigrants in the country legally, after accounting for deaths and departures.
In December 2024, the Census Bureau changed its U.S. population estimates, acknowledging much larger immigration flows than it had previously measured. Has this affected your estimates?
Yes. Since 2005, the American Community Survey (ACS) has provided the data we use to estimate the total number of immigrants living in the U.S. The population figures (or survey weights in the ACS) rely on another Census Bureau program that provides national and state-level population estimates each year.
Population estimates are released every December for the current year and all years since the most recent decennial census. Sometimes the bureau also changes the method for its estimates. It did that for its estimates released in December 2024, which covered 2021-24.
The new estimates changed how the bureau measured net international immigration in a major way. The updated national population estimates for 2023 included about 2 million more immigrants than the previous methodology had indicated. Almost all of those additional immigrants were unauthorized immigrants who had arrived since 2021.
Though the bureau updated its U.S. population estimates for 2022 and 2023, it did not retroactively adjust its surveys for those years or for the weights we use to estimate the number of immigrants. That means the data the bureau had previously released for those years is not consistent with its newer, better estimates.
For our new estimates of the unauthorized immigrant population, we reweighted the data for the 2022 and 2023 ACS so the estimates are comparable across years and align with the newer data on international migration. As a result, we revised our estimate of the unauthorized immigrant population for 2022 upward, from 11.0 million to 11.8 million.
Why are your most recent estimates from 2023? Isn’t there data for 2024 and 2025?
While there is some data for 2024 and 2025 that can shed light on trends in the unauthorized immigrant population, it’s less comprehensive and complete.
The ACS, our main data source, is not released until September and October of the year following the survey. As a result, the most recent ACS data we currently have is for 2023.
The Census Bureau’s Current Population Survey (CPS) is a more timely source, as it comes out monthly. But its scope is much more limited, and it samples only about 3% as many people as the ACS. That greatly limits its usefulness for estimating the size of the unauthorized immigrant population.
Nonetheless, CPS data and other federal sources can provide limited information about possible trends and changes in the total immigrant and unauthorized immigrant populations:
- For 2024, administrative data on arrivals of immigrants and CPS data on trends in the total immigrant population point to continued growth in the unauthorized immigrant population through the early part of the year. In the last half of 2024, that growth likely slowed.
- For 2025, monthly CPS data shows that the total immigrant population decreased by June, which implies that the unauthorized immigrant population did as well.
While we can’t definitively estimate the size of the unauthorized immigrant population from this data, the trends suggest that the unauthorized immigrant population was probably larger in mid-2025 than in 2023.
Can I calculate the number of unauthorized immigrants for 2024 and 2025 by adding the number of people that Border Patrol reported coming into the U.S. to your estimates?
No. It is correct that the people Border Patrol “releases” or “paroles” into the U.S. do count as unauthorized immigrants. However, adding these counts to our estimates will result in inaccurate totals because this does not account for other ways that the number of unauthorized immigrants can change.
Historically, the number of unauthorized immigrants has been very dynamic. The number can increase as more people enter the U.S. without authorization, overstay visas or are paroled into the country. It can also decrease as immigrants:
- Leave the U.S., either voluntarily or through deportation
- Die
- Become an LPR or get asylum
From 2007 through 2019, the number of unauthorized immigrants decreased by more than 2 million as more people left than entered the unauthorized immigrant population. On the other hand, it increased by nearly 4 million from 2019 through 2023.
How do you ensure your estimates are accurate?
We’ve changed our methodology over the years as more and better data has become available. Both parts of our estimate – the number of legal immigrants and the number of total immigrants – are based on data from reliable sources.
We also adjust our estimates to account for immigrants, both legal and unauthorized, who are missed in the national surveys. We use Census Bureau studies of undercount to make these adjustments.
We also use other data sources to assess the accuracy of our estimates, including data on birth rates and death rates as well as surveys and censuses in other countries. For example, Mexico, which accounts for the largest number of unauthorized immigrants to the U.S., has its own census and surveys that give us a better idea of how many unauthorized immigrants from Mexico we might be missing. We can then apply what we learn to the broader unauthorized immigrant population.
Finally, the ACS can be compared with the CPS, a smaller but more timely Census Bureau survey, to check the comparability of our estimates.