Barnwell County's 2026 population is estimated at 20,589, reflecting a 0.23% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Barnwell County is the 38th largest county in South Carolina. The 2010 population was 22,639 and has grown -9.06% since 2010.
Data after 2023 is projected based on recent change
Overall: 40.4 years
Female: 41.8 years
Male: 37.6 years
There are 15,651 adults, (3,927 of whom are seniors) in Barnwell County.
Female: 10,616 (51.7%)
Male: 9,905 (48.3%)
The racial composition of Barnwell County includes 52.22% White, 42.8% Black or African American, and smaller percentages for Two or more races, other race, Asian, Native American, Native Hawaiian or Pacific Islander and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 10,716 | 52.22% |
| Black or African American | 8,783 | 42.8% |
| Two or more races | 569 | 2.77% |
| Other race | 302 | 1.47% |
| Asian | 120 | 0.58% |
| Native American | 25 | 0.12% |
| Native Hawaiian or Pacific Islander | 6 | 0.03% |
Barnwell County 's average per capita income is $42,189. Household income levels show a median of $46,626. The poverty rate stands at 25.01%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $91,740 | - |
| Families | $63,603 | $80,569 |
| Households | $46,626 | $66,517 |
| Non Families | $25,283 | $38,221 |
Average Income
Median Household Income
Poverty Rate