In 2025, there were 177,784 illegal border crossings detected at the borders of the European Union, with the Central Mediterranean route detecting the highest number of crossings, at 66,328.

In FY 2025, the U.S. Border Patrol recorded some ******* enforcement encounters in the United States. This reflected a dramatic drop from the previous year, when encounters reached nearly **** million. These include both expulsion actions as well as apprehensions. 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. What is the U.S. Border Patrol? The U.S. Border Patrol (USBP) is primarily responsible for securing the borders of the United States in between official border crossings. It differs from the U.S. Immigration and Customs Enforcement (ICE), which is responsible for much of the federal government’s interior immigration enforcement. Immigration and political division While much to the U.S. population has 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.

According to Pew Research Institute estimates, the population of unauthorized immigrants in the United States reached a record of ** million people in 2023. The most recent estimate from the Department of Homeland Security (DHS) for 2022 put this figure at just under ** million people. Among U.S. states, California was believed to have the largest population of residents without legal status.

A line chart that shows Migrant encounters by U.S. Border Patrol at the U.S.-Mexico border, by month

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.

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

As of mid-2023, it was estimated that about **** million unauthorized immigrants from Mexico were living in the United States. It was also estimated that *** million immigrants without legal status from Guatemala were living in the United States. The Pew Research Institute estimated that the number of unauthorized immigrants nationwide reached ** million that year.

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.

In 2024, there were approximately 239,159 illegal border crossings made at borders of the European Union, with Syrian's being the most common nationality, at 44,237.

This dataset provides relevant figures concerning Mainland illegal immigrants apprehended and repatriated

In 2025, there were over 177,000 illegal border crossing detecting on the borders of the European Union, a substantial decline compared to 2023, when there were over 380,230. Illegal border crossings peaked in 2015 at the height of the European migrant crisis, when over 1.8 million illegal border crossings were detected.

Notes: Among adults 18 years and older. Differences in uninsured rates between lawfully present immigrants, likely undocumented immigrants, and U.S.-born citizens are statistically significant at p<0.05.

Users can download reports regarding immigrant issues and view maps of the distribution of the foreign-born population in the U.S. Topics include: immigration policy, migration, English language proficiency, and adult education. Background The Migration Policy Institute is a think tank dedicated to studying human migration across the globe. This website is useful for policymakers and practitioners interested in understanding and responding to immigrant integration. Topics include, but are not limited to: migration, immigration policy, English language proficiency, immigration enforcement, and English language education. User Functionality Users can download reports regarding immigrant int egration issues and immigration trends. Users can also access the State Responses to Immigration Database, the American Community Survey of the Foreign Born, and Who's Where in the United States Database. Users can download data into SAS statistical software. In addition, users can view maps showing the distribution of the foreign-born population in the U.S. Demographic information is available by race/ethnicity, Hispanic origin, place of origin, citizenship status, sex/gender, and marital status. Data Notes Data sources include the New Immigrants Survey, U.S. Department of State, U.S. Department of Homeland Security Office of Immigration Statistics, U.S. Department of Education, United States Census Bureau, U.S. Government Accountability Office (GAO), U.S. Customs and Border Protection, U.S. Immigration and Customs Enforcement (ICE), U.S. Citizen and Immigration Services, Congressional Research Service, Transactional Records Access Clearinghouse, National Immigration Law Ce nter, among others. Full citations and years to which the data apply, are indicated in each report. Data are available on national, state and city levels, depending upon the report.

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 33. Aliens Apprehended: Fiscal Years 1925 to 2019 (https://www.dhs.gov/immigration-statistics/yearbook/2019/table33)

Inspiration

The data was collected to observe trends in history reflecting the number of immigrants apprehended.