Illinois is home to one of the largest undocumented immigrant populations in the United States, with the vast majority residing in and around the Chicago metropolitan area.
As national debates over immigration policy continue, understanding the local realities—including which communities host the largest numbers—is critical for policymakers and residents alike. Recent data and research provide a detailed look at where undocumented immigrants live in Illinois, their demographic makeup, and their impact on local communities.
Chicago: The Undisputed Leader
Chicago stands out as the Illinois city with the highest undocumented immigrant population. According to the latest estimates, Chicago is home to approximately 183,000 undocumented immigrants, representing about 7% of the city’s total population. This makes Chicago not only the leader in Illinois but also one of the largest hubs for undocumented immigrants in the Midwest.
Within Chicago, certain neighborhoods have particularly high concentrations. South Lawndale (Little Village) is the community area with the largest number of undocumented immigrants, estimated at 20,000. Other neighborhoods with significant undocumented populations include Belmont Cragin (12,000), Gage Park (11,000), Albany Park (10,000), and Brighton Park (9,000).
Suburban Concentration and Regional Distribution
While Chicago proper has the single largest city population, the majority of Illinois’ undocumented immigrants—about 54%—actually live in the suburbs surrounding Chicago. Key counties with large undocumented populations include:
- Kane County: 43,000
- Lake County: 39,000
- DuPage County: 36,000
- Will County: 22,000
Notable suburban townships such as Aurora (23,000), Cicero (18,000), and Waukegan (14,000) each host thousands of undocumented residents.
Demographic Profile
Illinois’ undocumented immigrants are predominantly from Latin America, with Mexicans alone accounting for 77% of the total undocumented population. Asians make up about 9%, with the largest groups coming from the Philippines, India, Korea, and China. Europeans, mostly from Poland and Eastern Europe, represent another 5%.
The population skews young: 58% are between ages 25 and 44, and 11% are under 18. Most undocumented immigrants live in family households, often in mixed-status families that include U.S. citizens or legal residents.
Economic and Social Impact
Undocumented immigrants are deeply integrated into Illinois’ economy and society. They contribute an estimated $20.5 billion in household income and play significant roles in industries such as food service, accommodation, and technology. About 5% of all Illinois households—and more than 8% in Chicago—include at least one undocumented immigrant.
State Spending and Policy Context
Illinois has invested heavily in services for immigrants, including undocumented residents. By the end of 2025, the state is projected to have spent over $2.5 billion on migrant care, with health care being the largest expense. Programs like Health Benefits for Immigrant Seniors and Adults have experienced significant cost overruns, leading to policy changes such as the ending of the adult migrant program in July 2025.
Conclusion
Chicago remains the Illinois city with the largest undocumented immigrant population, serving as both a gateway and a home for hundreds of thousands of individuals and families. The city’s neighborhoods, especially South Lawndale (Little Village), are central to the state’s immigrant story.
As Illinois continues to debate and refine its immigration policies, the demographic and economic realities of its undocumented residents—most of whom live in mixed-status families and contribute significantly to the local economy—will remain a central consideration for lawmakers and communities alike.
Source:
[1] https://robparal.com/wp-content/uploads/Illinois-Undocumented-Immigrant-Population.pdf
[2] https://map.americanimmigrationcouncil.org/locations/illinois/
[3] https://www.illinoispolicy.org/think-illinois-spends-millions-on-migrants-wrong-it-spends-billions/
[4] https://www.americanimmigrationcouncil.org/wp-content/uploads/2025/01/immigrants_in_illinois.pdf
[5] https://www.migrationpolicy.org/data/unauthorized-immigrant-population/state/IL
[6] https://www.usnews.com/news/cities/slideshows/us-cities-with-the-most-immigrants-in-the-country-illegally
[7] https://en.wikipedia.org/wiki/Undocumented_immigrant_population_of_the_United_States
[8] https://www.pewresearch.org/short-reads/2024/07/22/what-we-know-about-unauthorized-immigrants-living-in-the-us/
[9] https://ohss.dhs.gov/sites/default/files/2024-06/2024_0418_ohss_estimates-of-the-unauthorized-immigrant-population-residing-in-the-united-states-january-2018%25E2%2580%2593january-2022.pdf
[10] https://cmsny.org/publications/the-undocumented-population-in-the-united-states-increased-to-12-million-in-2023/
[11] https://www.migrationpolicy.org/programs/data-hub/charts/us-immigrant-population-state-and-county
[12] https://www.higheredimmigrationportal.org/state/illinois/
[13] https://www.americanimmigrationcouncil.org/fact-sheet/immigrants-in-illinois/
[14] https://www.pewresearch.org/short-reads/2019/03/11/us-metro-areas-unauthorized-immigrants/
[15] https://usafacts.org/answers/how-many-immigrants-are-in-the-us/state/illinois/
[16] https://www.migrationpolicy.org/programs/us-immigration-policy-program-data-hub/unauthorized-immigrant-population-profiles
[17] https://www.epi.org/publication/unauthorized-immigrants/
[18] https://www.bushcenter.org/publications/monthly-immigration-update-may-2025