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.

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.

Acknowledgement

The following table is imported from the 2019 Yearbook of Immigration Statistics under the Department of Homeland Security:

The 2019 Yearbook of Immigration Statistics is a compendium of tables that provide data on foreign nationals who are granted lawful permanent residence (i.e., immigrants who receive a “green card”), admitted as temporary nonimmigrants, granted asylum or refugee status, or are naturalized. The Yearbook also presents data on immigration enforcement actions, including apprehensions and arrests, removals, and returns.

Table 39. Aliens Removed or Returned: Fiscal Years 1892 to 2019 (https://www.dhs.gov/immigration-statistics/yearbook/2019/table39)

Inspiration

The data was collected to observe trends in history reflecting the number of immigrants deported - more specifically removed or returned.

In 2024, when asked how undocumented immigrants to the United States should be handled, 39 percent of American survey respondents said that there should be a way for them to become legal U.S. residents and apply for citizenship. In 2022, it was estimated that there were about eleven million undocumented immigrants in the United States.

ABSTRACT

Statements about building walls, deportation and denying services to undocumented immigrants made by the US president may induce fear in Latino populations and create barriers to their health care access. To assess the impact of these statements on undocumented Latino immigrants' (UDLI) and Latino legal residents/citizens' (LLRC) perceptions of safety and their presentations for emergency care, we conducted surveys of adult patients at three county emergency departments (EDs) in California from June 2017 to December 2018. Of 1,684 patients approached, 1,337 (79.4%) agreed to participate: 34.3% UDLI, 36.9% LLRC, and 29.8% non-Latino legal residents/citizens (NLRC). The vast majority of UDLI (95%), LLRC (94%), and NLRC (85%) had heard statements about immigrants by President Trump. Most UDLI (89%), LLRC (88%), and NLRC (87%) either thought that these measures were being enacted now or will be enacted in the future. Most UDLI and LLRC reported that these statements made them feel unsafe living in the US, 75% (95% CI 70 to 80%) and 51% (95% CI 47 to 56%), respectively. More UDLI reported that these statements made them afraid to come to the ED (24% 95% CI 20 to 28%) vs LLRC (4.4% [95% CI 3 to 7%]) and NLRC (3.5% [95% CI 2 to 6%]); 55% of UDLI with this fear stated it caused them to delay coming to the ED (median delay 2-3 days). The vast majority of patients in our California EDs have heard statements about immigrants by the US president, which have induced worry and safety concerns in both UDLI and LLRC patients. These statements may also act as a barrier to some UDLI's access of emergency care. Given California's sanctuary state status, these safety concerns and ED access fears may be greater in a nationwide population of Latinos.

Statements about building walls, deportation and denying services to undocumented immigrants made during President Trump’s presidential campaign and presidency may induce fear in Latino populations and create barriers to their health care access. To assess how these statements relate to undocumented Latino immigrants’ (UDLI) and Latino legal residents/citizens’ (LLRC) perceptions of safety and their presentations for emergency care, we conducted surveys of adult patients at three county emergency departments (EDs) in California from June 2017 to December 2018. Of 1,684 patients approached, 1,337 (79.4%) agreed to participate: 34.3% UDLI, 36.9% LLRC, and 29.8% non-Latino legal residents/citizens (NLRC). The vast majority of UDLI (95%), LLRC (94%) and NLRC (85%) had heard statements about immigrants. Most UDLI (89%), LLRC (88%) and NLRC (87%) either thought that these measures were being enacted now or will be enacted in the future. Most UDLI and half of LLRC reported that these statements made them feel unsafe living in the US, 75% (95% CI 70–80%) and 51% (95% CI 47–56%), respectively. More UDLI reported that these statements made them afraid to come to the ED (24%, 95% CI 20–28%) vs LLRC (4.4%, 95% CI 3–7%) and NLRC (3.5%, 95% CI 2–6%); 55% of UDLI with this fear stated it caused them to delay coming to the ED (median delay 2–3 days). The vast majority of patients in our California EDs have heard statements during the 2016 presidential campaign or from President Trump about measures against undocumented immigrants, which have induced worry and safety concerns in both UDLI and LLRC patients. Exposure to these statements was also associated with fear of accessing emergency care in some UDLIs. Given California’s sanctuary state status, these safety concerns and ED access fears may be greater in a nationwide population of Latinos.

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.

From January to June 2025, the highest number of illegal immigrants that arrived in Spain via land and sea came from Mali, with approximately ***** people. The immigrants from Senegal and Algeria were the second and third most numerous group, with ***** and ***** people leaving their country of residence, respectively. More than ****** illegal immigrants reached the Iberian country in 2024. A risky journey Spain, together with Italy and Greece, are the main points of entry to Europe for illegal migration. Most arrivals happen through the Mediterranean Sea, which is a very dangerous journey for migrants. While active since 2006, the migration route from the coasts of West Africa to the Canary Islands (the closest territory of the European Union) has become particularly popular in recent years, even though so many people lost their lives their. Undocumented minors Among those reaching the Spanish territory are undocumented and unaccompanied minors, known in Spanish as "menas” (Menores Extranjeros No Acompañados). In 2018, the number of unaccompanied and separated children that arrived by sea exceeded *****, which represented the largest figure since at least 2014. This number decreased by approximately ***** cases in 2020. Nearly half of them came from Morocco, separated from Spain by merely ** kilometres of water at the Gibraltar Strait's narrowest point.

By providing nationality (region) by major category of residence qualifications and by gender, these are statistics as of the relevant point in time (year end), and the original statistics can be found in the Statistical Yearbook on the Immigration Bureau website. You can access it through the URL below. https://www.immigration.go.kr/immigration/1570/subview.do Click on the statistical yearbook for the relevant year - compressed Excel file - Status of foreign residents by nationality (region) and residence qualifications, and the statistical yearbook is published around the end of June every year. The statistics are for all foreigners, including illegal residents and those who have overstayed their stay period.

Forthcoming in Sociological ScienceI investigate whether the political ascent of Donald Trump, an adamant immigration restrictionist, during the 2016 presidential campaign was accompanied by decreasing support for the legalization of undocumented immigrants. Compiling survey data from 2012-2016, I show consistent support for legalization throughout the period. However, support was on the decline until Trump entered the presidential race in June 2015, rising thereafter. I use two Pew Research Center surveys, fielded in May 2015 and October 2016, to document that the increase in support for legalization was spearheaded by females, suburban residents, and self-identified Democrats. No demographic group, however defined, recorded a significant decline in their support for legalization. The political ascent of Donald Trump between mid-2015 and the presidential election of November 2016 was not associated with a decline in support for the legalization of undocumented immigrants but the opposite, consistent with similar trends recorded in Europe following the rise of right-wing parties. I discuss the implications of these findings for research on immigration attitudes.

To compare consultations with pregnant undocumented migrants at emergency primary health care to consultations with pregnant residents of Norway. A cross-sectional study of consultations at several time points. The study was conducted at the Oslo Accident and Emergency Outpatient Clinic (OAEOC), the main emergency primary care service in Oslo, Norway. Consultations with pregnant patients without a Norwegian identity number seeking care at the Department of Emergency General Practice at the OAEOC were identified through a manual search of registration lists from 2009 to 2019. The consultations were categorized by women’s residency status as ‘probably documented migrant’, ‘uncertain migrant status’, or ‘probably undocumented migrant’. We also extracted aggregated data for women with a Norwegian identity number (i.e. residents) presenting in consultations with pregnancy-related (ICPC-2 chapter W) conditions. Manchester Triage System urgency level at presentation, and hospitalization. Among 829 consultations with female patients categorized as probably undocumented migrants, we found 27.1% (225/829) with pregnant women. About half of the pregnant women (54.6% (123/225)) presented with a pregnancy-related condition. Pregnant women that were probably undocumented migrants had an increased risk of being triaged with a high level of urgency at presentation (relative risk (RR) 1.86, 95% CI 1.14–3.04) and being hospitalized (RR 1.68, 95% CI 1.21–2.34), compared to pregnant residents. Pregnant undocumented migrants were more severely sick when presenting to emergency primary care services than pregnant residents. Increased access to primary care and emergency primary care services for pregnant undocumented migrants is urgently needed. Restricted access to primary care may increase the use of primary care facilities intended for emergency care. A considerable proportion of the consultations with undocumented migrant women at the emergency primary care services are related to pregnancy. Consultations with pregnant undocumented migrants more often contained severe pregnancy-related conditions compared to consultations with pregnant residents of Norway. Interventions to increase access to primary care for pregnant undocumented migrants are urgently needed.

• Nationality of the interviewee.
• Most important problems in Spain. Problems that, personally, most affect you.
• Assessment of the protection offered by the State to different groups: elderly people living alone, unemployed pensioners and immigrants.
• Definition of immigration.
• Nationalities of immigrants.
• Estimation of the number of foreigners residing in Spain and in their place of residence.
• Assessment of the volume of immigrants living in Spain.
• Importance (0-10) of different aspects to allow the entry of an immigrant to Spain: good educational level, relatives living nearby, speak Spanish or regional language,...
• More appropriate policy regarding the entry of illegal immigrant workers and persons who have applied for political asylum. Tolerance with the laws regulating the entry of immigrants into Spain.
• Assessment (0-10) of the coexistence in Spanish society of people from different countries, cultures, religions and races.
• Treatment of foreign immigrants by Spaniards. Factor influencing such treatment.
• Positioning before the rights that stable and legal immigrants should have: family reunification, receipt of unemployment benefit, right to vote in municipalities, possibility of creating associations, and obtaining Spanish nationality.
• Agreement with phrases on health care and immigrants: the quality decreases due to the presence of immigrants, preference of Spaniards in access to health care,...
• Agreement with phrases on education and immigrants: the quality decreases due to the presence of immigrants, preference of Spaniards in access to a school place, investment should be increased,...
• Assessment of the compensation received by immigrants for what they contribute.
• Positive and negative aspects of immigration.
• Responsible for the integration of immigrants into society.
• Permissiveness with cultural and religious aspects of immigrants.
• Contribution of immigrants to the enrichment of Spanish culture.
• Agreement with phrases about the world of work and immigrants: they work in occupations that the Spaniards do not want, they work for lower wages, they take jobs,... Approval of situations resulting from the relationship between immigrants and natives: excluding a student for wearing a veil, hiring a Spaniard before an immigrant, protests over the construction of a mosque, expelling criminal immigrants.
• Assessment of immigration to Spain. Acceptance of various types of relationship with immigrants: cohabitation in the same neighborhood, in the same house, renting an apartment, at work, marriage / friendship with a child, ...
• Type of personal relationship of the interviewee with immigrants in Spain: neighborhood, friendship, work and family.
• Sympathy and antipathy towards different groups of immigrants. Reason for antipathy.
• Frequency of violent actions by immigrants against Spaniards.
• Justification of racism by violent phenomena of immigrants against Spaniards.
• Acceptance of a racist party in Spain.
• Punishment of citizens who utter racist insults.
• Elements that influence the image of immigration.
• The media's assessment of the image of immigration.
• Scale of trust in people (0-10).
• Ideological self-location of the interviewee (0-10).
• Voter turnout and recall in the 2008 general election.
• Possession of children of non-university school age and type of school in which they study.
• Type of health service, public or private, used.
• Stay at the place of residence of the interviewee. Time of residence in the city / town for those who have not always resided in the same place.
• Residence abroad of parents/relatives.
• Religious practice.
• Assessment of personal economic situation. Possibility of having been unemployed or threatened in the last 5 years.

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.

This survey collected responses from California residents on various issues. These include ratings of elected officials, party and registration status, opinions of possible candidates, proposed ballot initiatives, President Clinton, Whitewater, and immigration issues. These include the effects of illegal immigrants on California, refugees from various countries, and citizenship. Demographic data were also collected. These include age, education, political ideology, party affiliation, religiou s preference, income, ethnicity, race, and sex.

• Nationality of the person interviewed.
• Assessment of the protection offered by the State to different groups.
• Definition of immigration.
• Origin of immigrants that is most immediately thought of.
• Assessment of the number of immigrants currently in Spain.
• Scale of importance (0-10) of different aspects to allow the entry of an immigrant to Spain.
• More appropriate policy regarding the regularisation of illegal immigrants and asylum seekers.
• Degree of tolerance of the laws regulating the entry of immigrants into Spain.
• Rating scale (0-10) of the coexistence in Spanish society of people from different countries, cultures, religions and skin color.
• Treatment of foreign immigrants by Spaniards and factor influencing treatment .
• Treatment of foreign immigrants to Spaniards.
• Positioning before the rights that stable and legal immigrants should have.
• Degree according to phrases on health care and education and immigrants.
• Assessment of the compensation received by immigrants for what they contribute.
• Positive and negative aspects of immigration.
• Permissiveness with cultural and religious aspects of immigrants.
• Degree of contribution of immigrants to the enrichment of Spanish culture.
• Degree according to phrases about the world of work and immigrants in Spain.
• Degree of approval of situations resulting from the relationship between immigrants and natives.
• Positive/negative assessment of immigration to Spain.
• Acceptance of different types of relationships with immigrants, Roma and other religions.
• Presence of immigrants among their neighbors, co-workers or students, friends and relatives.
• Presence of Roma people among their neighbours, co-workers or students, friends or relatives.
• Presence of people of other religions among their neighbors, co-workers or students, friends and relatives.
• Sympathy/antipathy towards different groups of immigrants. Reason for antipathy towards different groups of immigrants.
• Assessment of violent actions of immigrants against Spaniards as a problem.
• Frequency of violent actions against immigrants. Punishment of citizens who utter racist insults or express opinions in public that incite xenophobia, racism and intolerance.
• Degree of acceptance of a racist party in Spain.
• Origin and perception of comments against immigrants.
• Degree of attention paid in the media to the issue of immigration and assessment conveyed by the media.
• Confidence scale (0-10) in people.
• Scale of racism (0-10).
• Ideological self-location scale (0-10).
• Voter turnout and recall in the 2011 general election.
• Possession of children of non-university school age and type of school in which they study.
• Type of health service, public or private, used.
• Civil status of the person interviewed.
• Situation of cohabitation of unmarried persons.
• Country of birth of the partner/spouse of the person interviewed.
• Year of arrival in Spain of the couple/spouse of the person interviewed.
• Stay at the place of residence of the interviewee.
• Time of residence in the city/town.
• Residence abroad of parents/relatives.
• Religiousness of the person interviewed.
• Assessment of personal economic situation.
• Subjective social class of the person interviewed.
• Retrospective possibility (5 years) of being unemployed.
• Household and personal income.
• Place of birth (country).
• Year since he has Spanish nationality.

This statistic shows the share of unauthorized adult immigrants by duration of residence in the U.S. in 2012. As of 2012, about ** percent of unauthorized adults have been living in the U.S. for 20 years or more.

Characteristics of undocumented migrants and uninsured legal residents tested for HIV (N = 439) by HIV status, in Amsterdam, the Netherlands, October 2018- October 2019.