The Migration Policy Institute says the Mexican-born population of the United States is getting smaller. Nationally, that holds. The count peaked above 11.7 million in 2007 and had slipped to roughly 11.1 million by 2024, even as the total immigrant population kept climbing. Chicago went the other way.
Two numbers, opposite directions. The gap is the story. And it matters because the population that grew in Chicago in 2024 became, in the months that followed, the primary target of the largest federal immigration operation the city has seen in a generation.
What the national data show
MPI’s Spotlight, by Andres Ayala and Jeanne Batalova, describes a population that is large and long-settled. Mexicans remain the biggest immigrant group in the country, about 22 percent of 50.2 million immigrants. Most arrived before 2010. When Mexicans obtain green cards, they do it overwhelmingly through family — roughly 90 percent of Mexican green-card recipients in FY 2024, against 63 percent for all new permanent residents. Labor-force participation runs high. Educational attainment and income run below the national immigrant average. About a third are naturalized citizens.
Put plainly: a settled, working, family-based population, most of it here more than fifteen years, most of it still without citizenship.
Border numbers have collapsed, and two of them are worth keeping straight. Border Patrol apprehensions between the official ports of entry — people caught crossing illegally, away from the checkpoints — fell to about 237,500 on the Southwest border in FY 2025, the lowest since 1970; Mexicans were 47 percent of them. Total Southwest border encounters, which add everyone processed at the ports of entry themselves — those found inadmissible or asking for protection — came to about 444,000, down from 2.1 million a year earlier. The first number is a slice of the second. Both fell by roughly 80 percent. Whatever is shrinking the national count, it is not new arrivals from Mexico.
So what is shrinking it? The government has an answer. In December 2025, DHS announced that more than 2.5 million people had “left” since January. Look closer.
| What DHS counts | Figure | How it is known |
|---|---|---|
| Deportations (formal removals) | 605,000 | Counted |
| “Voluntary self-deportations” | 1.9 million | Estimated from population surveys; its own CBP Home app logged about 13,000 by mid-2025 |
| Headline total | 2.5 million | Press release |
| Independent removal estimates (Brookings, MPI) | 310,000–340,000 | Analysts counting actual removals |
Treat the 2.5 million as what it is: a press release, not a count. Fear moves people, and the enforcement is real. A verified exodus of two and a half million is not.
Chicago against the trend
Illinois holds about 6 percent of the country’s Mexican immigrants, third behind California and Texas. Cook County is one of five counties — with Los Angeles, Harris, Maricopa, and Riverside — that together house roughly a quarter of every Mexican immigrant in the United States.
The 2024 city increase is real, but it needs context. Over the 2010s the metro area’s Mexican-born population fell, Cook County alone shedding tens of thousands. The 2024 figure reverses that slide. It comes from a single year of American Community Survey estimates, which swing more than multiyear data, so read it as a genuine uptick and not a boom. The longer truth is a population that thinned for a decade, then ticked back up in the year before the raids.
| Where Mexican immigrants concentrate (MPI, 2020–24) | Places |
|---|---|
| Top 5 metro areas (≈35% of all U.S. Mexican immigrants combined) | Los Angeles, Chicago, Houston, Dallas, Riverside |
| Top 5 counties (≈24% combined) | Los Angeles (CA), Harris (TX), Cook (IL), Maricopa (AZ), Riverside (CA) |
| Highest Mexican-born share of metro population | McAllen–Edinburg–Mission ≈25%, Riverside ≈12%, Greater L.A. ≈11% |
| Measure | Figure |
|---|---|
| Mexican-born residents, City of Chicago (2024) | ≈227,700, up 9% from ≈207,800 in 2023 |
| Total immigrants, City of Chicago (2024) | ≈597,400 — about 22% of the city; highest since 2006 |
| Cook County population | ≈5.2 million, second-largest U.S. county |
| Illinois active DACA recipients (Sept. 2025) | ≈26,850 |
| Illinois share of U.S. Mexican immigrants | ≈6% (third nationally) |
The profile is the caseload
For a lawyer, the demographic profile is not abstract. It predicts who walks in the door.
A population that is largely noncitizen, family-based, employed, and long-term resident is exactly the population most exposed when enforcement turns inward. These are not recent crossers with thin equities. They are people with a decade or more in the country, U.S.-citizen children, mortgages, and jobs — and, in many cases, no citizenship and no clean path to it. About a third of the national Mexican-born population lacks health insurance, the highest rate of any group MPI measured, which tells you something about how many work off the formal grid.
Mexicans are about 81 percent of the roughly 495,300 active DACA recipients nationwide as of December 2025. Illinois had about 26,850 as of September 2025. Every one of them is a person the government has on record as removable, protected only by a policy that has spent years in court. A shrinking national headcount does not shrink that exposure. It concentrates it in places like Chicago, where the population stayed.
The enforcement overlay
Began September 8, 2025, with more than 200 federal agents, some pulled from Los Angeles. The early phase had a face — Border Patrol commander-at-large Gregory Bovino — and a look: riot gear, pepper balls, running clashes through Pilsen and Little Village, the city’s Mexican core. After two U.S. citizens were shot and killed during his later surge in Minneapolis, Bovino was pulled from the role in January 2026 and replaced by border czar Tom Homan, who promised “targeted” operations instead. The spectacle gave way to something quieter and harder to see — arrests at courthouses and at immigration check-ins, where the government already knows exactly where you will be and when.
A 2022 settlement restricts warrantless immigration arrests in Illinois and five other states and requires probable cause plus a flight-risk showing before an arrest. Reported violations of that order have already produced court-ordered releases. Illinois lawmakers, meanwhile, stood up an accountability commission to document the operation, and its work carried into 2026.
None of this is peculiar to Chicago. The Migration Policy Institute, reading the same FY 2025 federal data, describes the through-line: once border crossings collapsed, the administration redirected its enforcement inward — toward the interior, toward cities. Chicago is where that turn pointed. Which raises a question the law has an answer to: where does “the border” end and “the interior” begin?
The border is not a line; it is a zone. Immigration officers may run warrantless searches for noncitizens “within a reasonable distance from any external boundary” (INA § 287(a)(3), 8 U.S.C. § 1357(a)(3)), and a regulation fixes that distance at 100 air miles (8 C.F.R. § 287.1(a)(2)). By the ACLU’s count, that band holds about two-thirds of the U.S. population and nine of the ten largest cities.
Expedited removal — deportation with no hearing, under 8 U.S.C. § 1225(b)(1) — was long a border tool. The 2004 rule reached only people caught within 100 miles of the border and present under 14 days. On January 21, 2025, DHS stretched it to anyone, anywhere, who cannot prove two years’ continuous presence. A district court paused the expansion in August 2025; in 2026 the D.C. Circuit let it take effect while the case goes on.
Chicago sits more than 100 air miles from the nearest international land border.
Here is the rub. The administration is treating the whole country as a border. It has taken tools built for the physical line — warrantless stops inside the hundred-mile zone, summary removal without a hearing — and pushed them inland, to Chicago and cities like it. The rationale amounts to this: the statute allows it, so they are doing it. That is ambitious, and it is a mess. It runs into the Fourth Amendment’s limits on suspicionless stops and the Fifth Amendment’s promise of a hearing, and it turns a long-settled resident’s ability to document two years into the only thing between them and a one-day deportation. A border is supposed to be a place. The government is trying to make it a condition that follows you.
Watch how it works now. The New York Times reported that TSA — the agency that screens you for a domestic flight — has been feeding passenger data to ICE, which mines it to find travelers to arrest. Agents have pulled people aside at check-in counters, gates, and jet bridges at more than a dozen airports, including travelers with pending applications and no criminal charge of any kind. A domestic boarding pass is not a border crossing. The government is treating it like one.
The national “decline” narrative can lull people into thinking the pressure is off. In Chicago it is the opposite. The population here is present, rooted, and growing, which is precisely why enforcement in this city falls on settled families rather than on anyone who just crossed a border. The people most likely to be taken are the people most likely to have been here longest.
The other big cities
Chicago is not alone, and it is not the largest concentration. Los Angeles County remains the single biggest home for Mexican immigrants in the country. Greater Los Angeles, Houston, Dallas, and Riverside round out the top five metros with Chicago. Where MPI reports the share of a metro’s residents born in Mexico, the border regions lead — roughly a quarter of the McAllen–Edinburg–Mission area — followed by Riverside and greater Los Angeles near 11 to 12 percent. One population, spread thin across a few states, now worked city by city.
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The Castañon Nava enforcement litigation — the closest thing to a brake on warrantless arrests in Illinois.
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The accountability commission’s findings — which may feed further suits.
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DACA — still unresolved, still the only thing standing between tens of thousands of Illinois residents and the removability they acknowledged when they applied.
Download the Chicago fact sheet (PDF)
Much of the data here — the demographic profile, the metro and county distribution, the unauthorized and DACA estimates — comes from the Migration Policy Institute, a nonpartisan research institution founded in 2001. MPI builds its numbers from Census and federal data, and it shows its work. That matters. When the government’s own headline is a press release — 2.5 million “left” — the count you can actually check comes from independent institutions like MPI. Explore their research at migrationpolicy.org.
Sources
National profile and Illinois share: Ayala & Batalova, Mexican Immigrants in the United States (MPI, 2025).
Demographic profile: U.S. Census Bureau, 2024 ACS S0201; Income, Poverty, and Health Insurance: 2024.
Green cards / family-based: DHS OHSS, 2024 Yearbook, Table 3.
Border encounters: CBP, Nationwide Encounters; Pew (Gramlich, 2026).
Unauthorized population: Gelatt, Ruiz Soto & Bachmeier (MPI, 2025).
DACA (national, Dec. 31, 2025): USCIS, Active DACA Recipients, FY2026 Q1; MPI DACA data tools. Illinois figure (Sept. 30, 2025): USCIS, Active DACA Recipients by State.
Metro and county distribution: MPI Migration Data Hub.
Chicago ACS figures: U.S. Census Bureau, 2024 ACS, as reported by WBEZ (Sept. 12, 2025). Cook County population: U.S. Census Bureau, 2024 estimates.
Enforcement: contemporaneous reporting (Chicago Sun-Times, USA Today, Block Club Chicago, WBEZ); Castañon Nava v. DHS settlement (2022); Ruiz Soto, A New Era of Immigration Enforcement (MPI, Oct. 2025).
National “departures” claim and its limits: DHS, More than 2.5 Million Illegal Aliens Left the U.S. (Dec. 10, 2025); independent removal estimates near 310,000–340,000 from MPI and Brookings.
Interior enforcement and the 100-mile zone: 8 U.S.C. § 1357(a)(3); 8 C.F.R. § 287.1(a)(2); expedited removal, 8 U.S.C. § 1225(b)(1); Designating Aliens for Expedited Removal, 69 Fed. Reg. 48877 (Aug. 11, 2004) and the DHS expansion notice (Jan. 21, 2025); ACLU, The Constitution in the 100-Mile Border Zone.
Chicago operation and airport enforcement: reporting on Operation Midway Blitz, Gregory Bovino, and Tom Homan (Chicago Sun-Times, NBC Chicago, ABC7, AP); The New York Times on TSA–ICE passenger-data sharing and arrests of domestic travelers at U.S. airports.
