Collinsville, Illinois population
Incorporated place · Official geographic code 1715599 · Census name: Collinsville city
· Annual resident population estimate
U.S. Census Bureau · Population Estimates Program · Vintage 2025
-93 residents (-0.39%) since July 1, 2024.
Collinsville had an estimated 23,717 residents on July 1, 2025, the 96th most populous of 1,294 incorporated places in Illinois. Its population fell 0.39% between July 2024 and July 2025, compared with +0.13% for Illinois and +0.52% for the United States.
- Population change, 2020–2025
- -646July 1 to July 1 · -2.65%
- Land-area density, 2025
- 1,536.3People per square mile · 2025 land area
- Rank in Illinois, 2025
- 96 of 1,2941,670 of 19,471 nationally
Collinsville population history
Open historical explorerThe six July 1 estimates in the table belong to one consistent Vintage 2025 series. The Census Bureau revises earlier years when it releases a new vintage; a figure from an older publication may differ from the value below.
Vintage 2025, July 1, 2020–2025 Intercensal, 2010–2020
The highest observed population in this annual series was 24,363 in 2020. This is a peak within 2020–2025 coverage, not an all-time record.
| Reference date | Population | Annual change |
|---|---|---|
| July 1, 2020 | 24,363 | — |
| July 1, 2021 | 24,202 | -161 |
| July 1, 2022 | 24,012 | -190 |
| July 1, 2023 | 23,888 | -124 |
| July 1, 2024 | 23,810 | -78 |
| July 1, 2025 | 23,717 | -93 |
Why is the April 2020 estimates base different from a census count?
The PEP estimates base here is 24,404 residents on April 1, 2020. It incorporates the Census Bureau’s corrections and geographic revisions and serves as the starting point for this annual series. It is not labeled an original 2020 census count. The chart starts at July 1, 2020, so its five-year change uses two July observations. Read about measurement types.
Collinsville population by year, 2010–2020
From the April 2010 estimates base to the April 2020 census count, Collinsville lost 1,222 residents (-4.8%). These Census Bureau intercensal estimates use 2020 boundaries and were released in November 2024.
| Date | Population | Annual change |
|---|---|---|
| April 1, 2010 · estimates base | 25,591 | — |
| July 1, 2010 | 25,574 | — |
| July 1, 2011 | 25,407 | -167 |
| July 1, 2012 | 25,291 | -116 |
| July 1, 2013 | 25,138 | -153 |
| July 1, 2014 | 24,972 | -166 |
| July 1, 2015 | 24,841 | -131 |
| July 1, 2016 | 24,744 | -97 |
| July 1, 2017 | 24,802 | +58 |
| July 1, 2018 | 24,631 | -171 |
| July 1, 2019 | 24,474 | -157 |
| April 1, 2020 · census count | 24,369 | — |
The April 2020 census count (24,369) and the Vintage 2025 April 2020 base (24,404) differ by 35. The gap comes from boundary changes and the Census Bureau’s revised 2020 base, not population change, so measure growth within one series. Source and download
Growth and density
Between July 1, 2020 and July 1, 2025, Collinsville lost 646 residents, a 2.65% decrease. The annualized change over these five elapsed years was -0.54%. Annualized change is a summary of the interval; it does not imply that the population changed at that rate in every year.
The 2025 Gazetteer reports 15.44 square miles of land. Dividing the July 1, 2025 population by that compatible land area gives 1,536.3 people per square mile. Water area is excluded. Density depends on geographic boundaries. It describes this entire place, rather than a typical neighborhood or built-up area.
Calculations use unrounded source values. Population counts are displayed as integers, percentages to two decimals and density to one decimal. Calculation methods · Growth calculator
How Collinsville compares
Growth rates below use the same Vintage 2025 series for every row, so they can be compared directly. A city’s rate can differ sharply from its county’s because the county also includes other towns and unincorporated areas.
| Geography | Population · 2025 | Growth · 2024–25 | Growth · 2020–25 |
|---|---|---|---|
| Collinsville | 23,717 | -0.39% | -2.65% |
| Madison County | 263,110 | -0.08% | -0.99% |
| St. Clair County | 250,708 | -0.27% | -2.47% |
| Illinois | 12,719,141 | +0.13% | -0.60% |
| United States | 341,784,857 | +0.52% | +3.08% |
The Census Bureau does not publish births, deaths or migration for incorporated places; county profiles show those components of change. Coverage details
Collinsville demographics: age, race and income
The median age in Collinsville is 38.5 years, compared with 39.0 in Illinois. 31.0% of adults 25 and older hold a bachelor’s degree or higher, and the median household income is $67,612. About 12.0% of residents live below the poverty level, and 3.1% were born outside the United States.
These are American Community Survey 5-year estimates for 2020–2024. They describe the 60 months ending in December 2024, come from a sample survey with the margins of error shown, and are separate from the July 1, 2025 population estimate above.
| Characteristic | Collinsville | Margin | Illinois | U.S. |
|---|---|---|---|---|
| Age and sex | ||||
| Median age | 38.5 | ±2.0 | 39.0 | 38.9 |
| Under 18 years | 19.7% | ±2.6 | 21.8% | 22.0% |
| 65 years and over | 18.2% | ±2.0 | 17.0% | 17.2% |
| Female | 51.2% | ±2.1 | 50.6% | 50.5% |
| Race and Hispanic origin | ||||
| Hispanic or Latino (any race) | 6.7% | ±1.8 | 18.8% | 19.3% |
| White alone, not Hispanic | 70.6% | ±3.6 | 58.1% | 57.4% |
| Black alone, not Hispanic | 16.1% | ±3.2 | 13.3% | 11.9% |
| Asian alone, not Hispanic | 1.2% * | ±0.9 | 5.9% | 5.9% |
| American Indian and Alaska Native, not Hispanic | 0.0% | ±<0.1 | 0.1% | 0.5% |
| Native Hawaiian and Pacific Islander, not Hispanic | 0.0% * | ±0.1 | 0.0% | 0.2% |
| Some other race, not Hispanic | 0.0% * | ±0.1 | 0.4% | 0.6% |
| Two or more races, not Hispanic | 5.5% | ±1.7 | 3.4% | 4.3% |
| Born outside the United States | 3.1% | ±0.9 | 14.7% | 14.1% |
| Households and education | ||||
| Households | 11,061 | ±427 | 5,036,449 | 129,227,496 |
| Average household size | 2.16 | ±0.08 | 2.46 | 2.53 |
| Bachelor’s degree or higher, age 25+ | 31.0% | ±3.1 | 37.8% | 35.7% |
| Income and poverty | ||||
| Median household income | $67,612 | ±$4,578 | $83,390 | $80,734 |
| Below the poverty level | 12.0% | ±2.6 | 11.8% | 12.5% |
Margins are 90% margins of error. * The margin is large relative to the estimate (coefficient of variation above 30%); treat it as approximate. Percentages are computed from published Summary File counts with Census Bureau margin formulas. ACS survey population: 24,031; 2024 boundaries. Source and download
Geographic context
This figure covers the residents inside Collinsville’s municipal boundary on July 1, 2025. It is not a metropolitan-area total, and figures for a ZIP code, school district or mailing address area cover different territory, so they usually differ. Collinsville lies in Madison County and St. Clair County, according to the published county/place-part relationships.
Illinois population · State city directory · City proper versus county versus metro
Other incorporated places in the same counties
Largest other whole incorporated places sharing at least one of these counties; their totals can include residents of neighboring counties.
| Place | Population · 2025 | Change · 2024–25 | Growth · 2024–25 | People / sq. mi. |
|---|---|---|---|---|
| Belleville | 40,237 | -305 | -0.75% | 1,731.0 |
| O'Fallon | 32,656 | +470 | +1.46% | 2,065.8 |
| Granite City | 26,807 | -113 | -0.42% | 1,409.8 |
| Edwardsville | 26,463 | -40 | -0.15% | 1,321.9 |
| Alton | 25,013 | -36 | -0.14% | 1,596.2 |
Illinois incorporated places with nearby population ranks
Neighboring 2025 population ranks within Illinois. Similar population does not imply similar density, boundaries or demographics.
| Place | Population · 2025 | Change · 2024–25 | Growth · 2024–25 | People / sq. mi. |
|---|---|---|---|---|
| Westmont | 24,155 | -36 | -0.15% | 4,798.2 |
| Melrose Park | 23,936 | -31 | -0.13% | 5,499.9 |
| Loves Park | 23,712 | +96 | +0.41% | 1,452.5 |
| Rolling Meadows | 23,690 | -39 | -0.16% | 4,216.9 |
Source, citation and downloads
U.S. Census Bureau, Population Estimates Program, Vintage 2025, sub-est2025.csv, variable POPESTIMATE2025; Collinsville city, Illinois, geographic code 1715599; resident population 23,717 on July 1, 2025; boundaries January 1, 2025. https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/cities/totals/sub-est2025.csv. Retrieved September 30, 2026. US Population Data snapshot pep-2025-r1, transformation 1.
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