Sullivan County's 2026 population is estimated at 20,660, reflecting a -0.26% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Sullivan County is the 70th largest county in Indiana. The 2010 population was 21,387 and has grown -3.4% since 2010.
Data after 2023 is projected based on recent change
Overall: 41.7 years
Female: 44.8 years
Male: 40.1 years
There are 16,873 adults, (3,937 of whom are seniors) in Sullivan County.
Female: 9,284 (44.7%)
Male: 11,496 (55.3%)
The racial composition of Sullivan County includes 90.66% White, 3.01% Black or African American, and smaller percentages for other race, Asian, Native American and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 18,839 | 90.66% |
| Two or more races | 1,066 | 5.13% |
| Black or African American | 625 | 3.01% |
| Other race | 153 | 0.74% |
| Asian | 80 | 0.38% |
| Native American | 17 | 0.08% |
Sullivan County 's average per capita income is $37,285. Household income levels show a median of $56,204. The poverty rate stands at 13.85%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $82,069 | $98,067 |
| Families | $72,848 | $88,018 |
| Households | $56,204 | $75,919 |
| Non Families | $33,726 | $50,829 |
Average Income
Median Household Income
Poverty Rate
