St. Clair County, Illinois Age & Gender Distribution (2024)
Population distribution by age and gender for St. Clair County, Illinois
St. Clair County, Illinois Age & Gender Statistics (2024)
Total Population
253,694
Median Age
39.9
Male Median
38.6
Female Median
40.9
St. Clair County, Illinois Population Growth
St. Clair County, Illinois Demographic Trend
Since 2010, the population of has changed by -4.9%%.
-4.9%% Growth
St. Clair County, Illinois Age & Gender Pyramid
Figure 2: Population distribution by age and gender for 2024.
St. Clair County, Illinois Historical Population Data
| Year | Median Age | Population |
|---|---|---|
| 2024 | 39.9 | 253,694 |
| 2023 | 39.5 | 254,777 |
| 2022 | 39.4 | 256,791 |
| 2021 | 39.2 | 258,597 |
| 2020 | 39.1 | 261,186 |
| 2019 | 38.6 | 262,338 |
| 2018 | 38.3 | 263,463 |
| 2017 | 38.0 | 264,433 |
| 2016 | 37.8 | 265,569 |
| 2015 | 37.7 | 267,029 |
| 2014 | 37.5 | 268,415 |
| 2013 | 37.3 | 268,939 |
| 2012 | 37.1 | 268,873 |
| 2011 | 36.9 | 268,086 |
| 2010 | 36.7 | 266,727 |
St. Clair County, Illinois Age Group Breakdown (2024)
| Age Cohort | Percentage |
|---|---|
| Under 5 | 5.7% |
| 5–17 | 17.3% |
| 18–24 | 8.1% |
| 25–34 | 12.7% |
| 35–54 | 25.3% |
| 55–64 | 13.5% |
| 65+ | 17.3% |
Dependency Ratios for St. Clair County, Illinois
- Total Dependency Ratio:
- 67.7
- Youth Dependency:
- 38.6
- Old-Age Dependency:
- 29.1
The dependency ratio measures dependents (ages 0-17 and 65+) per 100 working-age individuals (ages 18-64).
Age & Gender FAQs for St. Clair County, Illinois
The median age in St. Clair County, Illinois is 39.9 years.
According to latest Census data, the total population of St. Clair County, Illinois is 253,694.
In St. Clair County, Illinois, seniors (ages 65+) make up 17.3% of the population, while children under 18 represent 17.3%.
Based on historical data since 2010, the population in St. Clair County, Illinois is aging.