Which countries were the largest sources of undocumented migrants in the U.S. in 2025?

1. Mexico still tops the list, but its share has fallen

Scholars and federal data syntheses show Mexico remains the top origin country for the U.S. unauthorized population — about 5.5 million in mid‑2023 under MPI/CMS‑based estimates — yet that figure is well below Mexico’s 2007 peak and represents a shrinking share of the total undocumented population as arrivals from other regions have risen ^{[1] [3]}.

2. The Central American trio drives recent growth

Guatemala, Honduras and El Salvador together account for a large and growing slice of the unauthorized population; analysts note Central Americans have been the most significant contributors to growth since 1980 and made up roughly one‑fifth of undocumented residents in recent years, reflecting asylum‑driven flows and family networks ^{[5] [6] [2]}.

3. South American and Caribbean origins rose sharply in the early 2020s

Venezuela, Colombia, Brazil and Ecuador were identified as important South American source countries for unauthorized migrants, and parole programs and humanitarian pathways expanded arrivals from Venezuela, Cuba, Haiti and Nicaragua through 2023 — changes that analysts say materially altered the composition of the unauthorized population ^{[2] [4] [6]}.

4. Asia’s footprint grew: India and the Philippines among top non‑Western Hemisphere origins

Estimates and government border data indicate rising numbers from India and the Philippines, making them the leading non‑Western Hemisphere origin countries among the unauthorized population, a pattern linked to both visa overstays and increased overland and air migration routes in the early 2020s ^{[2] [3] [5]}.

5. Measurement, methodology and conflicting tallies matter

All of these conclusions are shaped by methodological choices: MPI’s estimates impute unauthorized status using pooled ACS and SIPP microdata weighted to academic benchmarks, while other organizations use CPS‑based or alternative modelling, producing different totals and rankings; major public reports therefore rely on mid‑2023 baselines and acknowledge that full 2024–2025 estimates remain provisional ^{[3] [2] [4]}. Critics and advocacy groups also publish divergent counts — for example, FAIR released a much higher 2025 estimate of the unauthorized population (about 18.6 million) that sits outside academic consensus — underscoring political stakes in headline numbers ^[7].

6. 2025 was a year of policy‑driven flux, so “largest sources” depend on timing

Policy actions — including pauses or terminations of parole programs, border processing changes, and stepped‑up enforcement — altered arrival flows and the stock of people classified as unauthorized between 2023 and 2025; Pew and other reviewers document rapid growth through 2023 followed by slowing or declines into 2025 tied to shifting administration policies, meaning country‑rankings for 2025 are best read as dynamic and contingent on which month and dataset are used ^{[4] [6]}.

Conclusion: a clear hierarchy, but with caveats

Using the best available, peer‑reviewed and academic‑linked estimates through mid‑2023 and the partial 2024–2025 records, Mexico is the largest single country of origin, followed by Guatemala, Honduras and El Salvador as the most important Central American sources, with Venezuela, Colombia, Brazil, Ecuador, the Philippines and India also among the leading origin countries — a picture repeatedly noted by Migration Policy Institute, EPI summaries, PBS and related analyses, all of which stress that 2025 figures remain influenced by policy changes and methodological limits ^{[1] [2] [3] [6] [4]}.