Which U.S. states have the largest undocumented immigrant populations and how have trends changed recently?
Executive summary
California, Texas, Florida, New York, New Jersey and Illinois together held the largest shares of the U.S. unauthorized (undocumented) population in recent estimates, accounting for roughly half to more than half of that population in 2023 depending on the data source (Pew Research Center/Axios) [1]. After years of relative geographic concentration, researchers report a sharp nationwide increase in the unauthorized population since 2019–2021 and an important redistribution across many states through 2023, though absolute totals and timing differ by methodology [2] [1] [3].
1. The big six: where most unauthorized immigrants live now
Multiple recent summaries identify California and Texas as the two states with the largest unauthorized populations, followed by Florida, New York, New Jersey and Illinois — a cluster that represented nearly 8 million people in 2023 according to Pew-derived reporting cited by Axios [1]. Visual mappings and long-standing state-level tables also show that populations remain concentrated in a relatively small set of large-economy states such as California and Texas, reflecting both labor markets and historic settlement patterns [4] [5].
2. How much did totals change recently — the debate between data sets
Researchers disagree on the exact nationwide total: Migration Policy Institute and other analysts describe large growth since 2019 (millions added through 2023) while Center for Migration Studies and other provisional CPS-derived estimates produced somewhat different point estimates [2] [3]. Pew’s reporting summarized by Axios places the U.S. unauthorized population growth as substantial between 2021 and 2023 and highlights a 2023 county/state distribution that shifts where people live [1]. Those differences reflect distinct methodologies and input data — a recurring source of variation across the literature [3].
3. Recent trend lines: growth, diversification, and geographic spread
The broad story from multiple analysts is a notable uptick in the unauthorized population from roughly 2019 to mid‑2023, driven by diverse flows (including arrivals at the U.S.–Mexico border, regional humanitarian crises, and visa overstays) and by secondary migration within the United States; Migration Policy Institute and related reviews document both growth and changing country-of-origin mixes in that period [2] [6]. Pew and other summaries emphasize that the unauthorized population became less concentrated in a handful of states — it grew in roughly three dozen states from 2021 to 2023 — even as large states still hold the largest absolute numbers [1].
4. Signs of turning points and uncertainty after mid‑2023
Some analysts note possible slowing of new arrivals after mid‑2023 because of stepped-up enforcement steps, policy changes, and Mexican enforcement that reduced border flows in 2024, but they caution that whether growth halted or reversed depends on policy and enforcement choices and on future migration pressures; these caveats arise in MPI and related commentary [2]. Meanwhile, provisional estimates from other groups show different timing and magnitudes of increases, underscoring ongoing measurement uncertainty [3].
5. Why the states ranking matters — and what the sources don’t settle
State rankings matter for policy, labor markets and local services, but interpretation requires care: large-state totals (California, Texas) are shaped by population size and economy, while percentage shares — and rapid recent gains in states like Florida — reflect new settlement patterns and origin-country shifts [1] [5]. The reporting assembled here cannot adjudicate which single estimate is “correct”; rather, it shows consistent signals — a post‑2019 rise and geographic dispersal — combined with substantive methodological disagreement across leading research groups [3] [2].