Jefferson County's estimated 2026 population is 35,659 with a growth rate of -0.62% in the past year according to the most recent United States census data. Jefferson County is the 38th largest county in Illinois. The 2010 population was 38,757 and has seen a growth of -7.99% since that time.
Data after 2023 is projected based on recent change
The racial composition of Jefferson County includes 84.88% White, 6.51% Black or African American, and smaller percentages for Asian, other race, Native American, Native Hawaiian or Pacific Islander and multiracial populations.
White (84.88%)
Two or more races (6.71%)
Black or African American (6.51%)
Asian (1%)
Other race (0.67%)
Native American (0.21%)
Native Hawaiian or Pacific Islander (0.02%)
Race | Population | Percentage (of total) |
|---|---|---|
| White | 31,241 | 84.88% |
| Two or more races | 2,471 | 6.71% |
| Black or African American | 2,398 | 6.51% |
| Asian | 369 | 1% |
| Other race | 245 | 0.67% |
| Native American | 76 | 0.21% |
| Native Hawaiian or Pacific Islander | 8 | 0.02% |
Married
Widowed
Divorced
Separated
Never Married
Jefferson County's average per capita income is $42,376. Household income levels show a median of $61,102. The poverty rate stands at 14.16%.
Name | Median | Mean |
|---|---|---|
| Married Families | $90,380 | $106,165 |
| Families | $74,499 | $90,351 |
| Households | $61,102 | $77,553 |
| Non Families | $34,689 | $48,822 |
Average Income
Median Household Income
Poverty Rate