The population of Illinois stands at approximately 12.7 million residents, positioning the state as the sixth-largest in the United States. While historic decades saw steady domestic migration away from the state, recent estimates from the U.S. Census Bureau show stabilizing trends driven by international migration and growth in key urban pockets.
Understanding where these numbers come from requires looking past the statewide total. Illinois features a sharp contrast between the massive metropolitan sprawl of Chicago and dozens of shrinking rural agricultural counties. This guide breaks down current population metrics, demographic shifts, regional distribution, and economic indicators.
Current Population and Growth Trends
Illinois recorded a total population of 12,812,508 during the official 2020 decennial census. Annual estimates place the figure close to 12.7 million. Although the state experienced small population declines in the late 2010s and early 2020s—leading to the loss of one congressional seat—recent tracking points toward stabilization.
Net migration patterns reveal a complex story. Thousands of residents leave annually for southern states like Florida and Texas due to cost of living and tax considerations. However, international migration into the Chicago metropolitan area regularly offsets these domestic losses.
Historical Context
To see how the state reached its current size, look at key milestone markers:
- 1900: 4.8 million residents
- 1950: 8.7 million residents
- 2000: 12.4 million residents
- 2020: 12.8 million residents
Growth was explosive through the mid-20th century, fueled by industrial manufacturing booms in Chicago, Peoria, and the Quad Cities. Growth slowed significantly after 1970 as industrial restructuring took hold across the Midwest.
Geographic Distribution and Regional Disparities
Population density across Illinois varies more than almost any other state outside of New York or California. More than half of all residents live within just three counties in the northeastern corner.
The Chicagoland Powerhouse
Cook County alone houses roughly 5.18 million people, making up over 40 percent of the state total. Combined with the collar counties of DuPage, Lake, Will, Kane, and McHenry, the greater Chicago metropolitan area accounts for nearly 65 percent of the entire state population.
Central and Southern Illinois
Outside of the Chicago orbit, population distribution thins out rapidly. Major regional hubs like Rockford, Peoria, Springfield, and Champaign-Urbana maintain stable or slowly growing populations anchored by universities and healthcare systems.
Conversely, deep southern counties—such as Alexander and Pulaski—have faced multi-decade population contractions exceeding 10 percent. Younger generations in these rural zones frequently move toward St. Louis suburbs (the Metro East area) or out of state for employment opportunities.
Demographic Breakdown
The population of Illinois is among the most diverse in the American Midwest, blending large minority communities with long-standing European-ancestry populations.
Race and Ethnicity
Data from the American Community Survey outlines the state's racial composition:
- White (Non-Hispanic): Approximately 57% to 58%
- Hispanic or Latino (Any race): Approximately 19% to 19.4%
- Black or African American: Approximately 13% to 14%
- Asian: Approximately 6%
- Two or More Races / Other: Approximately 4% to 9%
Illinois hosts the largest Hispanic community in the Midwest, concentrated heavily within Chicago and inner-ring suburbs. The state's Black population is also highly urbanized, with the majority residing in Chicago and the Metro East region near St. Louis.
Age Distribution
The median age in Illinois hovers around 39 years old, closely mirroring the national average.
- Residents under 18 years old comprise roughly 21% of the population.
- Adults aged 65 and older make up nearly 18% of the total, a share that continues to grow as the Baby Boomer generation ages.
Economy and Income Indicators
Population figures connect directly to economic performance. The median household income in Illinois stands at $86,676, outpacing the national median. High-income earners cluster heavily within corporate hubs in Chicago and technology-focused pockets near university towns like Champaign.
- Educational Attainment: Roughly 39% of residents hold a bachelor's degree or higher, exceeding historical averages and driving demand for professional service jobs.
- Employment Rate: The statewide employment rate rests near 61%, supported by a diverse economy spanning logistics, agriculture, finance, and advanced manufacturing.
Frequently Asked Questions
Is the population of Illinois growing or shrinking?
The population is currently stabilizing. While domestic out-migration remains a challenge, international migration and urban density in Chicagoland balance out losses, leading to minor annual gains.
What is the most populated city in Illinois?
Chicago is by far the largest city, housing roughly 2.7 million residents. Aurora, Naperville, Joliet, and Rockford follow as the next largest municipalities.
Why did Illinois lose a congressional seat?
Based on the 2020 census, Illinois experienced a minor population drop relative to booming sunbelt states like Texas and Florida. This slower relative growth triggered a constitutional reapportionment, reducing the state's U.S. House seats from 18 to 17.
How does Chicago's population compare to the rest of the state?
Chicago and its immediate collar counties account for nearly two-thirds of the total state population, creating a distinct economic and demographic divide between the metropolitan north and the rural south.
