Between 2021 and 2023, the number of unauthorized immigrants living in the United States increased from an estimated 10.5 million to 14 million, according to a new Pew Research Center report. This is the largest two-year increase with estimates over 30 years. The 14 million figure is also a new high, but preliminary data shows that the population continues to grow and likely peak in 2024.
In this Q&A, we talk with senior demographicist Jeffrey S. Passell about how the Center estimates the number of unauthorized immigrants in the United States.
How does Pew Research Center define “fraudulent immigration”? Jeffrey S. Passer, Senior Demographic S. Passel, Pew Research Center
Immigrants are people who are not members of the group that the United States has approved legal immigration. It has allowed legal permanent residents, refugees, asylum-related people, and legal temporary immigrants (for example, foreign students).
The term “illegal immigrant” combines immigrants whose status is non-permanent, unstable, or both. For example, many unauthorized immigrants have illegally entered the country. Others legally got in on work or on tourist visas, but stayed longer than permitted. And others legally entered the United States in a temporary and unstable position.
Although this term is not complete, it has been used by researchers for decades to estimate the size of this population, and is generally preferred over terms such as “undocumented immigration” and “illegal immigration.”
Why is it important to know how many unauthorized immigrants there are?
Unauthorized immigration accounts for around 4% of the US population. When government policies influence them, it is important to feel their number, who they are, and what their role is in the economy. Our estimates help provide insight into these factors, and how their population size has changed over time, where they came from, where they live in the United States, and how long they are here.
One example of what we can learn from these estimates is that many families in the United States include both fraudulent immigrants and American citizens. Approximately 12 million American citizens or legal immigrants live in households with at least one fraudulent immigrant.
How do unauthorized immigrants enter the country?
As mentioned before, unauthorized immigration enters the country in a variety of ways. Over the years, there have been two main categories of unauthorized immigrants.
People who legally enter the United States but illegally enter the United States who stay on a visa or otherwise violate the conditions of hospitalization.
Historically, the majority of unauthorized immigrants have entered the country illegally. In the 2010s, the share of staying visas increased.
In recent years, the federal government has created new programs, which has led to the third, but small category of unauthorized immigration.
People who enter the United States legally with temporary protection from deportation that governments can revoke if immigration policies change.
This third group includes immigrants from certain countries facing war, natural disasters or other crises, and individuals who have been parole or released at the US-Mexico border. In 2023, roughly 2 million of the 14 million unauthorized immigrants living in the country were hospitalized in the United States in unstable positions.
Why are those who have been given permission to come to the US or who are allowed to live and work here considered fraudulent immigrants?
In recent years, the number of immigrants has increased, and there has been a temporary position to protect them from deportation. They are grouped as fraudulent immigrants because their status can sometimes be quickly revoked by the President or Congress.
The Trump administration revoked protections for many unauthorized immigrants this year. More than half a million immigrants from Cuba, Haiti, Nicaragua and Venezuela, who were paroled to the US between October 2022 and November 2024, had their temporary protection removed in 2025, and their labor was invalidated.
How many migrants did these protections in 2023?
In 2023, more than 40% of unauthorized immigrants received some degree of protection from deportation. This is about 6 million out of an estimated total of 14 million people. This figure is a significant increase from 500,000 (or 4% of total) in 2007 and 2.7 million in 2021.
Protected groups include:
Asylum applications (2.6 million in 2023) Immigrants who entered the US legally after receiving parole (700,000) Victims of crimes or violence (700,000) Those with TPS (650,000) Enrolles in Deferred Action for Childhood Arrivals (DACA), a program for immigrants who were brought to the US illegally as children (600,000) Migrants who the US Border Patrol released into the US (1.0 million) How did you estimate the number of illegal immigrants in the United States?
Conceptually, the method of estimating the size of this population is fairly simple.
Estimate the number of immigrants legally in the country. Use national survey or census data to estimate the total number of migrants (legal and unauthorized) living in the country. Subtract the number of legal immigrants from the total.
Our methodology involves many details and improvements, but the basic calculations come from this simple relationship.
Data on the total immigrant population comes from a Census Bureau survey asking where respondents were born. (They don’t ask about the immigration situation.) These studies have a large sample and have been conducted over the years.
Annual data on the number of people recognized by the United States as legal permanent residents (also known as LPRS or green card holders) are available primarily from the Department of Homeland Security by refugees or people who are permitted to defect in asylum. Therefore, counting this group is easier than trying to directly count the number of fraudulent immigrants. Annual totals are used to legally estimate the current population of immigrants within the country after considering deaths and departures.
In December 2024, the Census Bureau changed its estimate of the US population, acknowledging a much larger migration flow than previously measured. Has this affected your estimate?
yes. Since 2005, the American Community Survey (ACS) has provided data to use to estimate the total number of immigrants living in the United States, and population figures (or weights of ACS surveys) rely on another Census Bureau program that provides national and state-level population estimates each year.
Population estimates are released every December this year and in all years since the latest decade census. Sometimes the department also changes the way it estimates. We did that from 2021 to 24 for estimates released in December 2024.
The new estimates changed how the Bureau measured net international migrants in key ways. The updated national population estimate for 2023 included roughly 2 million immigrants than previous methodologies showed. Almost all of these additional immigrants were unauthorized immigrants who had arrived since 2021.
The Bureau updated its estimates for the US population for 2022 and 2023, but did not retroactively adjust the survey for the weights it uses to estimate that year or the number of immigrants. This means that data previously released by the station does not match the newer, better estimates.
The new estimates of the unauthorized immigrant population measure ACS data again for 2022 and 2023, so the estimates are comparable over the years, consistent with new data on international migration. As a result, we revised our estimates of unauthorized immigrant populations from 110 million to 11.8 million in 2022.
Why are there the latest estimates for 2023? Are there any data for 2024 and 2025?
There are some data in 2024 and 2025 that can shed light on trends in unauthorized immigrant populations, but they are not comprehensive and complete.
The main data source, ACS, was not released until September and October of the year after the survey. As a result, the latest ACS data I currently have is 2023.
The Census Bureau’s current Census Survey (CPS) is a more timely source of information as it comes out every month. However, its range is much more limited, sampling only more people than ACS. This significantly limits its usefulness for estimating the size of unauthorized immigrant populations.
Nevertheless, CPS data and other federal sources can provide limited information on possible trends and changes in immigrants as a whole and injustice immigrant populations.
For 2024, management data on immigrant arrivals and CPS data on overall immigrant population trends show the continued growth of unauthorized immigrant populations at the beginning of the year. In the second half of 2024, its growth could be slower. In 2025, monthly CPS data shows that the total migrant population had declined by June. This means that the illicit immigrant population has done the same.
Although this data cannot clearly estimate the size of the rogue migrant population, this trend suggests that the unauthorized migrant population was probably larger in mid-2025 than 2023.
Can you calculate the number of unauthorized immigrants in 2024 and 2025 and add the number of people who reported that Border Patrols will come to your estimate?
no. People are right that “release” or “parole” counts as fraudulent immigrants on patrols to the US. However, adding these counts to the estimate results in an inaccurate sum, as it does not explain other ways in which the number of illicit immigrants could change.
Historically, the number of unauthorized immigrants has been very dynamic. It could increase as more people enter the United States without having to be approved, stay visas or parole within the country. It could also decrease as immigrants:
Leave the US voluntarily or through deportation, become LPR, or get exile
Between 2007 and 2019, the number of unauthorized immigrants fell more than 2 million, as more people remained than they entered the unauthorized immigrant population. Meanwhile, it increased nearly 4 million from 2019 to 2023.
How do you ensure that your estimate is accurate?
The methodology has been changed over the years as better data is now available. Both parts of the estimate – the number of legal immigrants and the total number of immigrants – are based on data from reliable sources.
They also adjust estimates to account for legal and unauthorized immigrants that have been overlooked in national investigations. We use undercount Census Bureau studies to make these adjustments.
We also use other data sources to assess the accuracy of estimates, including data on fertility and mortality, as well as surveys and census in other countries. For example, Mexico, which accounts for the largest number of unauthorized immigrants to the United States, has its own census and surveys that better consider how many unauthorized immigrants are missing. What you learn can then be applied to a wider unauthorized immigrant population.
Finally, ACS can be compared with CPS, a smaller, more timely Census Bureau survey, to see the comparability of estimates.
