How did the top countries of origin for illegal immigrants to the US change between 2020 and 2025?
Executive summary
Between 2020 and mid‑2025, Mexico remained the largest single country of origin for unauthorized immigrants to the United States, but its share of the unauthorized population fell while arrivals from Central America (Guatemala, Honduras, El Salvador) and several South American and Asian countries (notably India and the Philippines) grew — driven by record increases in arrivals in 2021–23 and then rapid policy‑driven shifts that reduced crossings in 2024–25 [1] [2] [3]. Border encounters spiked in 2021–23 and then dropped sharply after mid‑2024 and into early 2025, reshaping which nationalities were most visible at the border even as longer‑term unauthorized populations still reflected earlier patterns [4] [5] [6].
1. Mexico stayed on top, but its share fell: long‑term roots versus recent growth
Mexico has remained the largest origin country for U.S. immigrants and for unauthorized migrants in particular, but analysts show its relative share of the unauthorized population has declined from earlier decades even as its numeric unauthorized total rose modestly into 2022–23; Mexico accounted for roughly 5.5 million unauthorized migrants by mid‑2023 — well below its 2007 peak — and Mexico’s share dropped from about 62% in 2010 to roughly 40% in 2023, per researchers cited by Penn State and MPI [7] [8].
2. Central America surged as the most important driver of change
Guatemala, El Salvador and Honduras followed Mexico as the next largest origin countries and were the chief contributors to growth of the Central American‑born unauthorized population through 2021–23; Migration Policy Institute and other visualizations show the “Northern Triangle” as the principal source after Mexico during that period [1] [2].
3. Newer source countries expanded the unauthorized pool
Since 2020 the unauthorized population diversified: arrivals from South America (Venezuela, Colombia, Ecuador, Brazil) and from Asian countries (notably India and the Philippines) rose sharply in recent years, with analysts flagging unprecedented numbers of asylum seekers and border arrests of Indian nationals between 2018–23 [2] [1] [9]. This change is central to why Mexico’s share fell even while the total unauthorized population rose in 2021–23 [3] [10].
4. A boom (2021–23) then a policy pivot (mid‑2024 onward) altered visible flows
Encounters and arrivals surged after the pandemic lows of 2020 and peaked through 2021–23; official and congressional tallies emphasize large encounter totals in FY2021–24 that made the overall unauthorized population grow rapidly [4] [3] [11]. After mid‑2024, U.S. and Mexican policy actions — including asylum restrictions, parole program changes and increased Mexican enforcement — produced a rapid decline in encounters between late 2024 and early 2025, which in turn changed which nationalities were most frequently encountered at the border [5] [12] [6].
5. Short‑term encounter drops do not immediately erase longer‑term population shifts
Data for early 2025 show dramatic month‑to‑month drops in southwest border apprehensions (for example, February–April 2025 recorded very low monthly apprehensions compared with 2024), but researchers caution that encounter data measure border contact and enforcement activity, not the full stock of unauthorized residents — so country‑of‑origin shares in the resident unauthorized population can lag recent arrival patterns [13] [14] [6].
6. Conflicting narratives: enforcement success vs. broader population estimates
Government releases and Republican committee statements emphasize large reductions in encounters in early 2025 and say enforcement tightened the border [12] [13]. Independent researchers and Pew stress that the unauthorized population rose sharply through 2023 and was still likely larger in mid‑2025 than in 2023, and they note methodological limits in short‑term encounter counts versus population estimates [3] [6].
7. What the sources say — and what they don’t
Sources consistently identify Mexico, the Central American “Northern Triangle,” and growing shares from South America, India and the Philippines as the top origin places changing the mix since 2020 [1] [2] [10]. Available sources do not mention a definitive ranked list for “top countries in 2025 vs 2020” with exact percentage changes for every year; detailed, directly comparable country‑by‑country annual time series through 2025 are not presented in the materials provided (not found in current reporting).
Limitations and takeaways: estimates differ by methodology (encounters vs. resident population), policy shocks (Title 42, parole programs, Mexico enforcement) drove abrupt short‑term shifts in who was encountered at the border, and long‑term resident shares changed more slowly — Mexico stayed the largest origin but its share declined while Central American, South American and some Asian origin groups expanded [3] [1] [5].