Clay County's 2026 population is estimated at 12,573, reflecting a -0.98% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Clay County is the 81st largest county in Illinois. The 2010 population was 13,822 and has grown -9.04% since 2010.
Data after 2023 is projected based on recent change
Overall: 40.4 years
Female: 40.9 years
Male: 39.8 years
There are 9,941 adults, (2,727 of whom are seniors) in Clay County.
Female: 6,572 (50.4%)
Male: 6,480 (49.6%)
The racial composition of Clay County includes 95.24% White, and smaller percentages for other race, Black or African American, Asian, Native American and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 12,431 | 95.24% |
| Two or more races | 480 | 3.68% |
| Other race | 60 | 0.46% |
| Black or African American | 38 | 0.29% |
| Asian | 28 | 0.21% |
| Native American | 15 | 0.11% |
Clay County 's average per capita income is $42,390. Household income levels show a median of $60,417. The poverty rate stands at 17.51%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $88,895 | - |
| Families | $73,880 | $96,640 |
| Households | $60,417 | $78,529 |
| Non Families | $32,258 | $42,441 |
Average Income
Median Household Income
Poverty Rate