Marion County's 2026 population is estimated at 36,031, reflecting a -0.56% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Marion County is the 37th largest county in Illinois. The 2010 population was 39,416 and has grown -8.59% since 2010.
Data after 2023 is projected based on recent change
Overall: 41.5 years
Female: 42.5 years
Male: 40.5 years
There are 28,315 adults, (7,473 of whom are seniors) in Marion County.
Female: 18,791 (50.8%)
Male: 18,209 (49.2%)
The racial composition of Marion County includes 89.95% White, and smaller percentages for Black or African American, other race, Asian, Native American, Native Hawaiian or Pacific Islander and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 33,280 | 89.95% |
| Two or more races | 1,827 | 4.94% |
| Black or African American | 1,097 | 2.96% |
| Other race | 487 | 1.32% |
| Asian | 270 | 0.73% |
| Native American | 38 | 0.1% |
| Native Hawaiian or Pacific Islander | 1 | 0% |
Marion County 's average per capita income is $44,911. Household income levels show a median of $61,240. The poverty rate stands at 15.37%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $93,711 | $110,989 |
| Families | $77,328 | $94,619 |
| Households | $61,240 | $77,168 |
| Non Families | $36,548 | $46,149 |
Average Income
Median Household Income
Poverty Rate
