In 2022, an estimated 10.99 million unauthorized immigrants were living in the United States. This is an increase from about 3.5 million unauthorized immigrants who lived in the United States in 1990.

The estimated population of unauthorized immigrants in the U.S. stands at around ** million people. Although the number has stabilized, the United States has seen a spike in migrant encounters in the last few years, with over * million cases registered by the U.S. Border Patrol in 2023. This is a slight decrease from the previous year, when there were over *** million cases registered. Due to its proximity and shared border, Mexico remains the leading country of origin for most undocumented immigrants in the U.S., with California and Texas being home to the majority.

Immigration and political division

Despite the majority of the population having immigrant roots, the topic of immigration in the U.S. remains one of the country’s longest-standing political debates. Support among Republicans for restrictive immigration has grown alongside Democratic support for open immigration. This growing divide has deepened the polarization between the two major political parties, stifling constructive dialogue and impeding meaningful reform efforts and as a result, has led to dissatisfaction from all sides. In addition to general immigration policy, feelings toward illegal immigration in the U.S. also vary widely. For some, it's seen as a significant threat to national security, cultural identity, and economic stability. This perspective often aligns with support for stringent measures like Trump's proposed border wall and increased enforcement efforts. On the other hand, there are those who are more sympathetic toward undocumented immigrants, as demonstrated by support for the Deferred Action for Childhood Arrivals (DACA) program.

We apply standard demographic principles of inflows and outflows to estimate the number of undocumented immigrants in the United States, using the best available data, including some that have only recently become available. Our analysis covers the years 1990 to 2016. We develop an estimate of the number of undocumented immigrants based on parameter values that tend to underestimate undocumented immigrant inflows and overstate outflows; we also show the probability distribution for the number of undocumented immigrants based on simulating our model over parameter value ranges. Our conservative estimate is 16.7 million for 2016, nearly fifty percent higher than the most prominent current estimate of 11.3 million, which is based on survey data and thus different sources and methods. The mean estimate based on our simulation analysis is 22.1 million, essentially double the current widely accepted estimate. Our model predicts a similar trajectory of growth in the number of undocumented immigrants over the years of our analysis, but at a higher level. While our analysis delivers different results, we note that it is based on many assumptions. The most critical of these concern border apprehension rates and voluntary emigration rates of undocumented immigrants in the U.S. These rates are uncertain, especially in the 1990’s and early 2000’s, which is when—both based on our modeling and the very different survey data approach—the number of undocumented immigrants increases most significantly. Our results, while based on a number of assumptions and uncertainties, could help frame debates about policies whose consequences depend on the number of undocumented immigrants in the United States.

As of 2023, 27.3 percent of California's population were born in a country other than the United States. New Jersey, New York, Florida, and Nevada rounded out the top five states with the largest population of foreign born residents in that year. For the country as a whole, 14.3 percent of residents were foreign born.

In January 2022, it was estimated that about 1.85 million male illegal immigrants living in the United States were aged between 35 and 44 years old. In that same year, it was estimated that 1.52 million female illegal immigrants living in the U.S. were between 35 and 44 years old.

This graph shows the states with the highest search demand for immigration legal help, comparing 10 states and the number of undocumented immigrants. This also takes into consideration the % of undocumented immigrants, state laws on immigration enforcement (ranked 1-5), and search volume per 10k undocumented immigrants.

This statistic shows the estimated GDP loss if all illegal immigrant workers were removed from the United States. As of September 2016, the manufacturing industry would suffer an estimated 74 billion U.S. dollar decline in GDP output if all illegal immigrant workers were removed from the U.S.

Over 145,000 Venezuelans crossed illegally into Mexico in 2023. This year, Venezuela led the statistics of irregular migrants entering Mexico, followed by Honduras and Guatemala. Mexico is a well-known route for illegal immigration into the United States. Most of those migrants try to cross the board with the US.

Debates about migration are often in the news. People quote numbers about how many people are entering and leaving different countries. Governments need to plan and manage public resources based on how their own populations are changing.

Informed discussions and effective policymaking rely on good migration data. But how much do we really know about migration, and where do estimates come from?

In this article, I look at how countries and international agencies define different forms of migration, how they estimate the number of people moving in and out of countries, and how accurate these estimates are.

Migrants without legal status make up a small portion of the overall immigrant population. Most high-income countries and some middle-income ones have a solid understanding of how many immigrants live there. Tracking the exact flows of people moving in and out is trickier, but governments can reliably monitor long-term trends to understand the bigger picture.

Who is considered an international migrant? In the United Nations statistics, an international migrant is defined as “a person who moves to a country other than that of his or her usual residence for at least a year, so that the country of destination effectively becomes his or her new country of usual residence”.1

For example, an Argentinian person who spends nine months studying in the United States wouldn’t count as a long-term immigrant in the US. But an Argentinian person who moves to the US for two years would. Even if someone gains citizenship in their new country, they are still considered an immigrant in migration statistics.

The same applies in reverse for emigrants: someone leaving their home country for more than a year is considered a long-term emigrant for the country they’ve left. This does not change if they acquire citizenship in another country. Some national governments may have definitions that differ from the UN recommendations.

What about illegal migration? “Illegal migration” refers to the movement of people outside the legal rules for entering or leaving a country. There isn’t a single agreed-upon definition, but it generally involves people who breach immigration laws. Some refer to this as irregular or unauthorized migration.

There are three types of migrants who don’t have a legal immigration status. First, those who cross borders without the right legal permissions. Second, those who enter a country legally but stay after their visa or permission expires. Third, some migrants have legal permission to stay but work in violation of employment restrictions — for example, students who work more hours than their visa allows.

Tracking illegal migration is difficult. In regions with free movement, like the European Union, it’s particularly challenging. For example, someone could move from Germany to France, live there without registering, and go uncounted in official migration records.2 The rise of remote work has made it easier for people to live in different countries without registering as employees or taxpayers.

Prior research indicates the enforcement of immigration policy by the host country affects immigrants’ political behavior. Yet, its effect on their economic behavior – namely, remittances – remains understudied. To fill this gap, we theorize on remittances’ political determinants in the host country. In general, we argue remittance flows vary with subnational enforcement of the host country’s immigration policy. In particular, immigrants insure themselves against deportation by remitting more in highly punitive locales. We test our theory in the context of the United States’ Secure Communities program, a nationwide policy involving local-federal partnerships to identify and deport undocumented immigrants. We expect greater remittance inflows to Mexican states with more deportees under the program. Instrumental variable analysis affirms our expectation. Mexican states with more deportees under Secure Communities receive significantly more remittances than other Mexican states. The analysis illuminates the indirect effects of host countries’ enforcement of their immigration policy.

Significantly more men were apprehended by the United States Border Patrol than women in the the fiscal year of 2020. Nationwide, ******* men were apprehended by Border Patrol in that year, compared to ****** women who were apprehended.

This poll, fielded May 18-23, 2007, is a part of a continuing series of monthly surveys that solicit public opinion on the presidency and on a range of other political and social issues. An oversample of African Americans was conducted for this poll. Respondents were asked whether they approved of the way George W. Bush was handling the presidency and issues such as immigration and foreign policy. Views were sought on Vice President Dick Cheney, the United States Congress, the most important problem facing the country, and the condition of the national economy. Those who were registered to vote were asked how closely they were following the 2008 presidential campaign, whether they were more likely to vote in a Democratic or Republican primary, for whom they would vote, their opinion of the nominees from each party, and which party they trusted to handle foreign policy and immigration issues. A series of questions addressed immigration policy in the United States, the effect of legal and illegal immigration on the economy, society, crime, and terrorism, whether immigration should be kept at current levels, and respondents' opinions of proposed solutions for dealing with illegal immigration. Additional topics addressed the war in Iraq, abortion, baseball star Barry Bonds, and steroid use in professional sports. Information was also collected on whether respondents were born in the United States, whether they had been raised in a non-English speaking household, and whether they had regular contact with anyone who was a legal or illegal immigrant to the United States. Demographic information includes sex, age, race, education level, marital status, United States citizenship status, household income, religious preference, frequency of religious attendance, military service, political party affiliation, political philosophy, voter registration status and participation history, type of residential area (e.g., urban or rural), the presence of children under 18 and household members between the ages of 18 and 24, and whether respondents had children attending a four-year college.

The aim of the Transatlantic Trends Survey is to identify the attitudes of the public in the United States and European countries towards foreign policy issues and transatlantic issues. Transatlantic Trends: Immigration, a special topic public opinion survey conducted yearly since 2008, is a project of the German Marshall Fund of the United States. For 2011, the Immigration survey examined attitudes and policy preferences related to immigration in France, Germany, Italy, the United Kingdom, and the United States. This collection focused on respondent perceptions of legal and illegal immigrants, conditions for admittance of immigrants, level of support for policies to reduce immigration, preconditions for citizenship, and whether or not immigration enriched society. Respondents were asked to identify the most important issues facing their country, to evaluate their government's performance in managing immigration and the economy, whether immigration presented a national opportunity or a problem, and whether they believed immigrants were integrating well into society. Additional topics included the developments in North Africa and the Middle East, responsibility for displaced refugees coming from North Africa, and whether the respondent's nation should offer economic aid to countries committed to democracy. Lastly, respondents were asked about which political party they identified with, their voting intentions in the next national election, and whether political party agendas would influence their vote. Demographic and other background information includes gender, age, stage at which full-time education was completed, age when stopped full-time education, employment status, ethnic background, country of birth, citizenship, parents' citizenship status, type of phone line, ownership of a mobile phone, and the number of people in their household.

In 2022, about **** million illegal aliens were apprehended in the United States. This was a significant increase from the previous year, when there were around **** million illegal aliens apprehended nationwide. Apprehensions refer to Border Patrol apprehensions and ICE administrative arrests.

This poll, fielded May 20-24, 2010, is part of a continuing series of monthly surveys that solicits public opinion on the presidency and on a range of other political and social issues. Respondents were asked whether they approved of the way Barack Obama was handling his job as president, whether things in the United States were going in the right direction, and how they would rate the condition of the national economy. Respondents were also asked what they thought was the most important problem facing the United States today, whether they approved or disapproved of the way President Obama was handling the economy, the situation with Afghanistan, health care, and the threat of terrorism. They were also asked whether they approved of the way Congress was handling its job, whether most members of Congress have done a good enough job to deserve re-election, and whether they felt the economy is getting better or worse. They were also queried on their feelings for the Democratic and Republican parties, about the way things are going in Washington, DC, how important they thought it was for there to be another woman on the Supreme Court, and their opinion of Supreme Court nominee Elena Kagan. Respondents were asked how serious a problem they thought illegal immigration was, whether they thought the Arizona documentation policy went too far in dealing with illegal immigration, whether the federal government should have provided financial help to United States homeowners who were having trouble repaying their mortgages, whether the federal government should have provided financial help to United States automakers who were in financial trouble, and whether the federal government should have provided financial help to United States banks and financial institutions who were in financial trouble. Respondents were asked about the new health care reform bill and whether they approved it, and whether this new reform bill will mostly help, hurt, or not affect them. They were also queried on whether they favored increased drilling for oil and natural gas off the coast of the United States, whether they approved of the way the Obama Administration was handling the oil spill in the Gulf of Mexico, and whether they approved the way BP was handling the same oil spill. They were asked to rate their family financial situation, how concerned they were about making ends meet financially in the next 12 months, how concerned they were in the next 12 months they or someone in their household might be out of work, how much the economic recession affected them and their family, and whether the economic recession affected plans for their children's future. They were also asked their opinion of the Tea Party movement and whether they considered themselves to be a supporter of the Tea Party movement. They were also asked whether they thought being gay or homosexual was a choice, whether same-sex relations between consenting adults is wrong, whether it is necessary to have laws to protect gays and lesbians from discrimination in housing and employment, and whether they personally know someone who is gay or lesbian. Demographic information includes sex, age, race, education level, household income, military service, religious preference, reported social class, type of residential area (e.g., urban or rural), political party affiliation, political philosophy, voter registration status, and whether respondents thought of themselves as born again Christians.

This poll, fielded October 4-8, 2007, is a part of continuing series of monthly polls that solicit public opinion on various political and social issues. This poll focused on Virginia and the state elections. Virginia residents were asked what was the biggest issue facing Virginia at that time, whether they thought the state of Virginia was moving in the right direction, and to rate the condition of Virginia's economy. Several questions asked whether respondents approved of the way the Virginia state legislature was handling its job, and for opinions of Governor Tim Kaine, Senator James Webb, Senator John Warner, the Republicans and Democrats in the state legislature, Junior Senator Mark Warner, Former Governor Jim Gilmore, and Congressman Tom Davis. Respondents were asked how closely they had been following the races for general assembly and state senate in Virginia, how likely they would be to vote in the Virginia state elections and for whom they would vote if the 2008 United States senate race were being held that day, which political party they would like to see in control of the state legislature, and which issues would be most important in their vote for the Virginia state legislature. A series of questions asked respondents about immigration, including how many recent immigrants lived in the respondents' area at the time, how much contact they had with recent immigrants, their opinions of immigrants and how they affect the country, whether illegal immigration was a problem in their area, and how federal, state, and local governments should handle illegal immigration issues. Information was also collected on how closely respondents were following the 2008 presidential race, how likely they were to vote in the 2008 presidential primaries in their state, for whom respondents would vote if the Democratic and Republican primaries and presidential election were being held that day, and for their opinions on the 2008 potential presidential candidates. Respondents were asked which political party they trusted more to handle issues such as taxes and the war in Iraq, which political party they preferred the next president to belong to, as well as whether they approved of the way George W. Bush was handling the presidency. Additional topics included the Iraq War, traffic congestion in their area of the state, Virginia's transportation funding plan, and Virginia's law on abusive driver fees. Demographic information includes sex, age, race, education level, household income, religious preference, frequency of religious attendance, whether respondents considered themselves to be a born-again Christian, whether anyone in the household was a military veteran, marital status, type of residential area (e.g., urban or rural), whether respondents were born in the United States, how many years they had lived in the state of Virginia, voter registration status and participation history, political party affiliation, political philosophy, and the presence of children under the age of 18 in the household.

This study investigates how changes in immigration attitudes in an area spread to other localities. We use the exogenous variation in immigration attitudes from the Associated Press news wire service ban on the term ``illegal immigrant,'' which previous research has shown made immigration attitudes less hostile in more affected United States counties. We show that respondents in areas more socially connected (via Facebook) to those more affected by the ban exhibited improved immigration attitudes. Additional results suggest the likely channel is changing attitudes in socially connected counties and that people who use social media for political information are more affected.

Attitudes towards the topics of internal security, asylum, immigration and counter-terrorism.

1. Internal security: subjective feeling of security or concern about criminal attacks; assessment of relevant sources of fear of crime (e.g. through portrayals of violence on television, through the daily news about crime and criminality, own experiences of victimisation, etc.); concern about concrete crimes (attacks by Islamist terrorists, organised criminal gangs from abroad, young people´s propensity to violence, theft and assaults on the open street, break-ins and break-ins of cars, violence in the family, police assaults); assessment of policy efforts to ensure security; assessment of appropriate security measures (more visible presence of police and law enforcement officers, faster deportation of foreign criminals, law enforcement officers in public transport, video surveillance of public places and in public transport vehicles, tougher penalties, more intensive police checks on motorways, stronger internet surveillance, more social prevention projects for young people); assessment of stronger cooperation between different German and international security bodies (police authorities of the Federation and the federal states, police and intelligence services of the EU states, resp. police and intelligence services of Germany and the USA); attitude towards video surveillance in public places (feeling of security or rather of unease or both at the same time); attitude towards data retention.

2. Attitudes towards asylum and immigration: Dealing with refugees with rejected asylum applications (deportation or toleration under certain conditions); concern about the increase in the number of refugees; concrete concerns regarding the topic of asylum and refugees in Germany (alienation, increasing criminality, rise in right-wing radicalism, loss of German identity, increase in illegal immigrants in the country, excessive demands on social security systems); necessity of selected measures to improve and tighten asylum law (immediate deportation in the case of rejected asylum applications, work permits for asylum seekers, toleration despite rejection of the asylum application, stricter examination of the grounds for asylum); assessment of selected criteria for immigration to Germany (occupation in demand, family members in Germany, young or old, political persecution in home country, university degree, good knowledge of German, no criminal offences in home country, desire for education); opinion on the immigration of highly qualified skilled workers from abroad; assessment of the domestic significance of German immigration policy; assessment of the importance of a welcoming culture for immigrants; immigrants feel welcome vs. not welcome in Germany.

3. Counter-terrorism: assessment of the danger of terrorist attacks in Germany; assessment of the federal government´s efforts with regard to protection against a terrorist attack; opinions on punishment of financial supporters and of sympathisers of terrorist organisations.

Demography: sex; age; highest level of education; employment; occupational status; marital status (household structure); religious denomination; net household income.

Additionally coded were: Respondent ID; weighting factor; city size; federal state.

This poll, conducted April 6-9, 2006, is part of a continuing series of monthly surveys that solicit public opinion on the presidency and on a range of other political and social issues. Respondents were asked to give their opinions on the current direction of the country, the most important problem the country is facing, the national economy, and to rate the job performance of the United States Congress. Respondents were also asked about the way George W. Bush was handling certain issues, such as the economy, immigration, the war in Iraq, and terrorism, whether or not they approved of his overall job performance, and whether or not he and his policies would affect the way they would vote in Congressional elections. The next section of the survey addressed immigration, legal and illegal immigrants, amnesty, and a security fence between the United States and Mexico. The survey also contained questions about Pope Benedict XVI, the Catholic clergy, various religious groups, Creationism, the Bible, and the respondent's religious background, beliefs, and practices. Respondents were then asked for their opinions on the Republican and Democratic parties, and the war in and the future of Iraq. Additional questions solicited information on whether or not the respondents or someone they knew had served in Iraq, as well as the respondents' television news viewing habits. Background information on respondents includes military service, voter registration status, party identification, marital status, sex, religious preference, education record, age, ethnicity, and income.

In 2022, the greatest number of illegal aliens returned in the United States were from the Philippines, with ****** illegal aliens returned. India, Canada, China, and Russia rounded out the top five in that year.