Clay County's 2026 population is estimated at 14,939, reflecting a -1.01% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Clay County is the 14th largest county in South Dakota. The 2010 population was 13,830 and has grown 8.02% since 2010.
Data after 2023 is projected based on recent change
Overall: 24.9 years
Female: 24.1 years
Male: 26.5 years
There are 12,574 adults, (1,856 of whom are seniors) in Clay County.
Female: 7,625 (50.1%)
Male: 7,594 (49.9%)
The racial composition of Clay County includes 84.98% White, 3.77% Native American, and smaller percentages for Asian, Black or African American, other race, Native Hawaiian or Pacific Islander and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 12,933 | 84.98% |
| Two or more races | 939 | 6.17% |
| Native American | 574 | 3.77% |
| Asian | 452 | 2.97% |
| Black or African American | 278 | 1.83% |
| Other race | 32 | 0.21% |
| Native Hawaiian or Pacific Islander | 11 | 0.07% |
Clay County 's average per capita income is $46,842. Household income levels show a median of $56,850. The poverty rate stands at 19.73%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $107,706 | - |
| Families | $99,644 | $118,864 |
| Households | $56,850 | $78,631 |
| Non Families | $31,386 | $41,639 |
Average Income
Median Household Income
Poverty Rate