Unauthorized Immigration Flows Before and After COVID-19

The U.S. economy’s recovery from the shocks of the COVID-19 pandemic included a strong rebound in the labor market. The demand for workers created a surge in U.S. job openings, which, among other factors, contributed to a surge in unauthorized immigration to the country.

In this blog post, we first look at the evolution of attempts at unauthorized immigration from January 2020 to January 2025. We measure this flow by examining monthly nationwide encounters reported by U.S. Customs and Border Protection (CBP), which tracks interactions between CBP officials and people attempting to enter the U.S. without required authorization.People unauthorized to enter the U.S. include those who attempted to enter illegally and had no grounds to remain and those who were encountered at the point of entry without authorization but were allowed to remain temporarily as they seek humanitarian protection before an immigration court. Not all people enter the country for the purpose of immigration; some may enter for temporary work or so they can cross into Canada. Also, not all unauthorized immigrants entered the U.S. illegally; many entered with valid visas but overstayed the period of visa validity. To focus on recent trends, we concentrated on unauthorized immigration attempts at different entry points, including land borders. The aggregate number of encounters reported by CBP for these entry points is a reasonable proxy for attempted unauthorized immigration flows. Next, we use fiscal year data for a longer time horizon to see how the attempted unauthorized immigration flows in the years following the start of the COVID-19 pandemic compare with those in prepandemic years going back to 2012. In that context, we also look at people who may have entered the U.S. illegally and evaded detection. Finally, we discuss how some characteristics of the unauthorized immigrant pool, such as English proficiency, educational attainment and age distribution, have changed since 2008.

Monthly Nationwide Encounters since 2020

The first figure below breaks down by family status the nationwide number of foreign nationals who attempted to enter the U.S. without authorization and were encountered by CBP officials from January 2020 to January 2025, the month with the most recent available data. In April 2020, the month following the COVID-19 emergency declaration in the U.S., encounters dropped sharply but then rebounded. A steady rise in the number of encounters began in the second half of 2020.

Nationwide Encounters with Customs and Border Protection, by Family Status

SOURCES: Customs and Border Protection and authors’ calculations.

NOTES: A family unit comprises one or more minors plus their parent(s) or legal guardian(s) with whom they are traveling; the data represent the number of individuals in these family units. “Other” comprises two separate CBP categories: single adults and certain accompanied children; these accompanied children are in a distinct category from children encountered as part of family units. For precise definitions of these categories, see this glossary at the U.S. Office of Homeland Security Statistics.

In March 2021, there was a sharp uptick in encounters, which continued until the end of 2023. However, since the beginning of 2024, we see a moderation and then a steady downward trend starting in the summer of that year. Most encounters in 2024 continued to be with single adults. Families have generally represented the second largest share over this time, while the number of unaccompanied children encountered by the CBP has been relatively small.

CBP Encounters and Estimates of Those Who Evaded Detection since Fiscal Year 2012

The figure below presents data available by fiscal yearThe federal government’s fiscal year begins on Oct. 1 and ends on Sept. 30 of the next calendar year. For example, fiscal year 2024 began on Oct. 1, 2023, and ended on Sept. 30, 2024. for the number of foreign nationals who attempted to enter the U.S. without authorization and were encountered by the CBP, as well as the estimates for the number of those who evaded the CBP and entered illegally.CBP uses the term “gotaways” to describe these individuals. Both categories are generally stable until the onset of COVID-19 in the U.S. in fiscal year 2020. Consistent with the first figure, we see sharp increases after fiscal year 2020 and then a more recent moderation.

Nationwide CBP Encounters and Estimates of Foreign Nationals Who Evaded CBP

SOURCES: Office of Homeland Security Statistics, Department of Homeland Security, Customs and Border Protection, and authors’ calculations.

NOTE: To calculate these evasion estimates, we took the official number of detected evasions and adjusted for estimated evasions that were undetected and for recidivism.

To gauge the evolution of the scale of those who evaded the CBP, we separately calculated that category as a percentage of total attempts at unauthorized immigration (individuals with CBP encounters and those who evaded the CBP). We found that this percentage was at 20% in fiscal year 2020 and remained at about 20% through fiscal year 2023; it then dipped to about 10% in fiscal year 2024.

Educational and Other Demographic Characteristics since 2008

The next figure examines the evolution of English proficiency and educational attainment of the unauthorized immigrant pool, i.e., those who entered the U.S. and were now residing in the country. We used an algorithm developed by George Borjas and Hugh Cassidy to impute unauthorized status for foreign-born persons sampled in the American Community Survey.See George J. Borjas and Hugh Cassidy’s 2019 article, “The Wage Penalty to Undocumented Immigration,” in Labour Economics.

English Proficiency and Higher Education Attainment among Immigrants Residing in the U.S. without Authorization

SOURCES: American Community Survey, Borjas and Cassidy (2019) and authors’ calculations.

NOTE: Proficient in English is defined as meeting either of the ACS categories: speaking only English at home or speaking English very well if they speak another language at home.

Both timelines show an initial increase between 2008 and 2020, but more mixed trends since 2020. English proficiency slightly declined in 2023 compared with the level in 2020, while the share of those holding a bachelor’s degree remained almost unchanged between the corresponding years.

Turning to the age composition in the next figure, we find fairly stable shares among different age groups over the years. An overwhelmingly large share (at 88%) of immigrants lacking authorization were in the 18-64 age group in 2023 compared with a corresponding share of about 61% for the U.S. population.

Age Composition of Immigrants Residing in U.S. without Authorization

SOURCES: American Community Survey, Borjas and Cassidy (2019) and authors’ calculations.

Conclusion

There has been a marked uptick in unauthorized immigration in recent years, but the latest data show some moderation. Since 2008, English proficiency and educational attainment levels among immigrants residing in the U.S. without authorization increased until 2020. Since then, the progress on these metrics has been mixed. Meanwhile, the age composition of this immigrant pool has remained quite stable over the years and tilted overwhelmingly toward a working-age span of 18 to 64.

The authors thank economist Seth Murray for several helpful suggestions.

Notes

1. People unauthorized to enter the U.S. include those who attempted to enter illegally and had no grounds to remain and those who were encountered at the point of entry without authorization but were allowed to remain temporarily as they seek humanitarian protection before an immigration court. Not all people enter the country for the purpose of immigration; some may enter for temporary work or so they can cross into Canada. Also, not all unauthorized immigrants entered the U.S. illegally; many entered with valid visas but overstayed the period of visa validity. To focus on recent trends, we concentrated on unauthorized immigration attempts at different entry points, including land borders. The aggregate number of encounters reported by CBP for these entry points is a reasonable proxy for attempted unauthorized immigration flows.
2. The federal government’s fiscal year begins on Oct. 1 and ends on Sept. 30 of the next calendar year. For example, fiscal year 2024 began on Oct. 1, 2023, and ended on Sept. 30, 2024.
3. CBP uses the term “gotaways” to describe these individuals.
4. See George J. Borjas and Hugh Cassidy’s 2019 article, “The Wage Penalty to Undocumented Immigration,” in Labour Economics.