Sully County's 2026 population is estimated at 1,434, reflecting a -1.17% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Sully County is the 62nd largest county in South Dakota. The 2010 population was 1,377 and has grown 4.14% since 2010.
Data after 2023 is projected based on recent change
Overall: 46.9 years
Female: 47.5 years
Male: 46.4 years
There are 1,190 adults, (353 of whom are seniors) in Sully County.
Female: 684 (44.8%)
Male: 842 (55.2%)
The racial composition of Sully County includes 86.5% White, 4.52% Black or African American, 3.93% Native American, and smaller percentages for other race and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 1,320 | 86.5% |
| Two or more races | 71 | 4.65% |
| Black or African American | 69 | 4.52% |
| Native American | 60 | 3.93% |
| Other race | 6 | 0.39% |
Sully County 's average per capita income is $48,446. Household income levels show a median of $72,578. The poverty rate stands at 6.32%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $103,828 | - |
| Families | $98,906 | $117,446 |
| Households | $72,578 | $105,002 |
| Non Families | $55,469 | $85,854 |
Average Income
Median Household Income
Poverty Rate