What we know about unauthorized immigrants living in the U.S. (2024)

The unauthorized immigrant population in the United States reached 10.5 million in 2021, according to new Pew Research Center estimates. That was a modest increase over 2019 but nearly identical to 2017.

The number of unauthorized immigrants living in the U.S. in 2021 remained below its peak of 12.2 million in 2007. It was about the same size as in 2004 and lower than every year from 2005 to 2015.

The new estimates do not reflect changes that have occurred since apprehensions and expulsions of migrants along the U.S.-Mexico border started increasing in March 2021. Migrant encounters at the border have since reached historic highs.

How we did this

Pew Research Center undertook this research to understand ongoing changes in the size and characteristics of the unauthorized immigrant population in the United States. The Center has published estimates of the U.S. unauthorized immigrant population for more than two decades. The estimates presented in this research are the Center’s latest, adding new and updated annual estimates for 2017 through 2021.

Center estimates of the unauthorized immigrant population use a “residual method.” It is similar to methods used by the U.S. Department of Homeland Security’s Office of Immigration Statistics and nongovernmental organizations, including the Center for Migration Studies and the Migration Policy Institute. Those organizations’ estimates are generally consistent with ours. Our estimates also align with official U.S. data sources, including birth records, school enrollment figures and tax data, as well as Mexican censuses and surveys.

Our “residual” method for estimating the nation’s unauthorized immigrant population includes these steps:

  1. Estimate the total number of immigrants living in the country in a particular year using data from U.S. censuses and government surveys such as the American Community Survey and the Current Population Survey.
  2. Estimate the number of immigrants living in the U.S. legally using official counts of immigrant and refugee admissions together with other demographic data (for example, death and out-migration rates).
  3. Subtract our estimate of lawful immigrants from our estimate of the total immigrant population. This provides an initial estimate of the unauthorized immigrant population.

Our final estimate of the U.S. unauthorized immigrant population, as well as estimates for lawful immigrants, includes an upward adjustment. We do this because censuses and surveys tend to miss some people. Undercounts for immigrants, especially unauthorized immigrants, tend to be higher than for other groups. (Our 1990 estimate comes from work by Robert Warren and John Robert Warren; details can be found here.)

The term “unauthorized immigrant” reflects standard and customary usage by many academic researchers and policy analysts. The U.S. Department of Homeland Security’s Office of Immigration Statistics also generally uses it. The term means the same thing as undocumented immigrants, illegal immigrants and illegal aliens.

For more details on how we produced our estimates, read the Methodology section of our November 2018 report on unauthorized immigrants.

Who are unauthorized immigrants?

The unauthorized immigrant population includes any immigrants not in the following groups:

  1. Immigrants admitted for lawful residence (i.e., green card admissions)
  2. People admitted formally as refugees
  3. People granted asylum
  4. Former unauthorized immigrants granted legal residence under the 1985 Immigration Reform and Control Act
  5. Immigrants admitted under any of categories 1-4 who have become naturalized U.S. citizens
  6. Individuals admitted as lawful temporary residents under specific visa categories

Read the Methodology section of our November 2018 report on unauthorized immigrants for more details.

Pew Research Center’s estimate of unauthorized immigrants includes more than 2 million immigrants who have temporary permission to be in the United States. (Some also have permission to work in the country.) These immigrants account for about 20% of our national estimate of 10.5 million unauthorized immigrants for 2021.

Although these immigrants have permission to be in the country, they could be subject to deportation if government policy changes. Other organizations and the federal government also include these immigrants in their estimates of the U.S. unauthorized immigrant population.

Immigrants can receive temporary permission to be in the U.S. through the following ways:

Temporary Protected Status (TPS)

In 2021, there were about 500,000 unauthorized immigrants with Temporary Protected Status. This status provides protection from removal or deportation to individuals who cannot safely return to their country because of civil unrest, violence or natural disaster.

Deferred Enforced Departure (DED) is a similar program that grants protection from removal. The number of immigrants with DED is much smaller than the number with TPS.

Deferred Action for Childhood Arrivals (DACA)

Deferred Action for Childhood Arrivals is a program that offers protection from deportation to individuals who were brought to the U.S. as children before June 15, 2007. As of the end of 2021, there were slightly more than 600,000 DACA beneficiaries, largely immigrants from Mexico.

Asylum applicants

Individuals who have applied for asylum but are awaiting a ruling are not legal residents yet but cannot be deported. There are two types of asylum claims, defensive and affirmative.

Defensive asylum applications are generally filed by individuals facing deportation or removal from the U.S. These are processed by the Department of Justice’s Executive Office for Immigration Review. At the end of 2021, there were almost 600,000 applications pending.

Affirmative asylum claims are made by individuals already in the U.S. who are not in the process of being deported or removed. These claims are handled by the U.S. Department of Homeland Security’s Citizenship and Immigration Services (USCIS). At the end of 2021, more than 400,000 applications for affirmative asylum were pending, some covering more than one applicant.

Here are key findings about how the U.S. unauthorized immigrant population changed from 2017 to 2021:

  • The most common country of birth for unauthorized immigrants is Mexico. However, the population of unauthorized immigrants from Mexico dropped by 900,000 from 2017 to 2021, to 4.1 million.
  • There were increases in unauthorized immigrants from nearly every other region of the world – Central America, the Caribbean, South America, Asia, Europe and sub-Saharan Africa.
  • Among U.S. states, only Florida and Washington saw increases to their unauthorized immigrant populations, while California and Nevada saw decreases. In all other states, unauthorized immigrant populations were unchanged.
  • 4.6% of U.S. workers in 2021 were unauthorized immigrants, virtually identical to the share in 2017.

Trends in the U.S. immigrant population

The U.S. foreign-born population was 14.1% of the nation’s population in 2021. That was very slightly higher than in the last five years but below the record high of 14.8% in 1890.

As of 2021, the nation’s 10.5 million unauthorized immigrants represented about 3% of the total U.S. population and 22% of the foreign-born population. These shares were among the lowest since the 1990s.

Between 2007 and 2021, the unauthorized immigrant population decreased by 1.75 million, or 14%.

Meanwhile, the lawful immigrant population grew by more than 8 million, a 29% increase, and the number of naturalized U.S. citizens grew by 49%. In 2021, naturalized citizens accounted for about half (49%) of all immigrants in the country.

Where unauthorized immigrants come from

Unauthorized immigrants living in the U.S. come from many parts of the world, with Mexico being the most common origin country.

The origin countries for unauthorized immigrants have changed since the population peaked in 2007, before the Great Recession slowed immigration. Here are some highlights of those changes:


The number of unauthorized immigrants from Mexico living in the U.S. (4.1 million in 2021) was the lowest since the 1990s. Mexico accounted for 39% of the nation’s unauthorized immigrants in 2021, by far the smallest share on record.

The decrease in unauthorized immigrants from Mexico reflects several factors:

  • A broader decline in migration from Mexico to the U.S.
  • Mexican immigrants to the U.S. continuing to return to Mexico
  • Expanded opportunities for lawful immigration from Mexico and other countries, especially for temporary agricultural workers.

The rest of the world

The total number of unauthorized immigrants in the U.S. from countries other than Mexico has grown rapidly. In 2021, this population was 6.4 million, up by 900,000 from 2017.

Almost every region in the world had a notable increase in the number of unauthorized immigrants in the U.S. from 2007 to 2021. The largest increases were from Central America (240,000) and South and East Asia (180,000).

After Mexico, the countries of origin with the largest unauthorized immigrant populations in the U.S. in 2021 were:

  • El Salvador (800,000)
  • India (725,000)
  • Guatemala (700,000)
  • Honduras (525,000)

India, Guatemala and Honduras all saw increases from 2017.

The Northern Triangle

Three Central American countries – El Salvador, Honduras and Guatemala – together represented 2.0 million unauthorized immigrants in the U.S. in 2021, or almost 20% of the total. The unauthorized immigrant population from the Northern Triangle grew by about 250,000 from 2017 and about 700,000 from 2007.

Other origin countries

Venezuela was the country of birth for 190,000 U.S. unauthorized immigrants in 2021. This population saw particularly fast growth, from 130,000 in 2017 and 55,000 in 2007.

Among countries with the largest numbers of U.S. unauthorized immigrants, India, Brazil, Canada and former Soviet Union countries all experienced growth from 2017 to 2021.

Some origin countries with significant unauthorized immigrant populations showed no change, notably China (375,000) and the Dominican Republic (230,000).

Detailed table: Unauthorized immigrant population by region and selected country of birth (and margins of error), 1990-2021 (Excel)

U.S. states of residence of unauthorized immigrants

The unauthorized immigrant population in most U.S. states stayed steady from 2017 to 2021. However, four states saw significant changes:

  • Florida (+80,000)
  • Washington (+60,000)
  • California (-150,000)
  • Nevada (-25,000)

States with the most unauthorized immigrants

The six states with the largest unauthorized immigrant populations in 2021 were:

  • California (1.9 million)
  • Texas (1.6 million)
  • Florida (900,000)
  • New York (600,000)
  • New Jersey (450,000)
  • Illinois (400,000)

These states have consistently had the most unauthorized immigrants since 1990 and earlier.

At the same time, the unauthorized immigrant population has become less geographically concentrated. In 2021, these six states were home to 56% of the nation’s unauthorized immigrants, down from 80% in 1990.

Detailed table: Unauthorized immigrant population for states (and margins of error), 1990-2021 (Excel)

Detailed table: Unauthorized immigrants and characteristics for states, 2021 (Excel)

Unauthorized immigrants in the labor force

The share of unauthorized immigrants in the U.S. workforce was slightly less than 5% in 2021, compared with 3% of the total U.S. population.

Demographics help explain the difference: The unauthorized immigrant population includes relatively few children or elderly adults, groups that tend not to be in the labor force.

Overall, about 7.8 million unauthorized immigrants were in the U.S. labor force in 2021. That was up slightly from 2019 but smaller than every year from 2007 through 2015.

Detailed table: Unauthorized immigrants in the labor force for states, 2021 (Excel)

Here are some additional findings about unauthorized immigrants as a share of the workforce nationwide and in certain states:

  • Since 2003, unauthorized immigrants have made up 4.4% to 5.4% of all U.S. workers, a relatively narrow range.
  • Fewer than 1% of workers in Maine, Montana, Vermont and West Virginia in 2021 were unauthorized immigrants.
  • Nevada (9%) and Texas (8%) had the highest shares of unauthorized immigrants in the workforce.
What we know about unauthorized immigrants living in the U.S. (2024)


What is a person living in the U.S. without legal immigration status? ›

Legal immigrants are foreign-born people legally admitted to the U.S. Undocumented immigrants, also called illegal aliens, are foreign-born people who do not possess a valid visa or other immigration documentation, because they entered the U.S. without inspection, stayed longer than their temporary visa permitted, or ...

What do you know about immigration in the United States? ›

In 2019, 44.9 million immigrants (foreign-born individuals) comprised 14 percent of the national population. The United States was home to 22.0 million women, 20.4 million men, and 2.5 million children who were immigrants.

What difficulties did immigrants to the United States face explain your answer? ›

What difficulties did new immigrants face in America? Immigrants had few jobs, terrible living conditions, poor working conditions, forced assimilation, nativism (discrimination), anti-Aisan sentiment.

How do undocumented immigrants become documented? ›

Undocumented immigrants must come forward and register, submit biometric data, pass criminal background and national security checks, and pay fees and penalties before they will be eligible for a provisional legal status.

Can you live in the U.S. legally without being a citizen? ›

Nonimmigrant Visas. To immigrate to the United States means to relocate permanently by obtaining a green card (officially known as an “immigrant visa” or “lawful permanent residence”). A green card allows unrestricted employment and can be renewed indefinitely. It also provides a pathway to U.S. citizenship.

How long can you live in the U.S. without being a citizen? ›

An immigrant (US permanent resident Green Card holder) who has been living in the USA at least 5 years and who satisfies all of the other eligibility requirements can become an American citizen through naturalization.

Why are migrants coming to the US? ›

The expected surge can be attributed not only to seasonal migration patterns, but an increase of people displaced by war, poverty, and climate factors in all continents.

Who are the largest immigrants in the US? ›

Immigrants from Mexico have comprised the largest group since 1980, but the composition of new arrivals has changed since the Great Recession of 2007-09. By 2013, India and China had displaced Mexico as the top origins for new arrivals.

What country takes in the most immigrants? ›

The United States of America has been the main country of destination for international migrants since 1970. Since then, the number of foreign-born people residing in the country has more than quadrupled – from less than 12 million in 1970, to close to 51 million in 2019.

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The social problems of immigrants and migrants include 1) poverty, 2) acculturation, 3) education, 4) housing, 5) employment, and 6) social functionality.

What was the biggest challenge faced by immigrants to the United States? ›

The language barrier is one of the biggest problems most immigrants face in the U.S. If you don't speak English at all, everything from getting a job to buying food can be extremely difficult.

How are immigrants affecting the US? ›

However, although immigrants increase the supply of labor, they also spend their wages on homes, food, TVs and other goods and services and expand domestic economic demand. This increased demand, in turn, generates more jobs to build those homes, make and sell food, and transport TVs.

Can an illegal immigrant marry a U.S. citizen? ›

In fact, it is common to see U.S. citizens marrying undocumented immigrants. Illegal immigrants may marry U.S. citizens, as long as the marriage is genuine. However, it must be taken into account whether the undocumented person in question entered the country legally or illegally.

Can a U.S. citizen adopt an illegal immigrant? ›

To Adopt a Foreign-Born Person, They Must Be Under 16

For immigration purposes, only children can be adopted, and the adoption must be finalized before the child turns 16 years of age. Because adoption itself can be a lengthy process, you're probably better off starting when the child is age 15 or younger.

How long does it take for an undocumented immigrant to become a citizen? ›

In general, a noncitizen must spend at least 5 years as a lawful permanent resident to be eligible for naturalization while a spouse of a U.S. citizen must spend at least 3 years as a lawful permanent resident. The median years spent as an LPR for all citizens naturalized in FY 2023 was 7 years.

What does it mean to be without lawful immigration status? ›

It means that you have not entered a country (a legally defined domain) through approved channels, and having done so you have either not applied for asylum, had the application finally refused with no right of further appeal and not left, overstayed your visa, or in some other way evaded the rule of law.

What is a non immigrant resident? ›

Nonimmigrant status

This status is for people who enter the U.S. on a temporary basis – whether for tourism, business, temporary work, or study. Once a person has entered the U.S. in nonimmigrant status, they are restricted to the activity or reason for which they were allowed entry.

What does non immigration status mean? ›

The U.S. government uses the term nonimmigrant to refer to foreign nationals who are admitted to the United States temporarily for a specific purpose. By contrast, the term immigrant refers to foreign nationals who wish to come to the United States permanently.

What is a non citizen immigrant? ›

Lawfully Present “Non-Qualified” Immigrants/Nonimmigrants. These are non-citizens who are lawfully present in the U.S. and are not included in the definition of qualified immigrants listed above. Common non-qualified immigrants include: • Immigrants paroled into the U.S. for less than one year.


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