Lyman County's 2026 population is estimated at 3,723, reflecting a 0.03% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Lyman County is the 43rd largest county in South Dakota. The 2010 population was 3,761 and has grown -1.01% since 2010.
Data after 2023 is projected based on recent change
Overall: 36.1 years
Female: 36.2 years
Male: 36.1 years
There are 2,681 adults, (682 of whom are seniors) in Lyman County.
Female: 1,776 (47.7%)
Male: 1,948 (52.3%)
The racial composition of Lyman County includes 57.89% White, 39.39% Native American, and smaller percentages for Two or more races, Native Hawaiian or Pacific Islander, other race, Black or African American, Asian and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 2,156 | 57.89% |
| Native American | 1,467 | 39.39% |
| Two or more races | 74 | 1.99% |
| Native Hawaiian or Pacific Islander | 13 | 0.35% |
| Other race | 12 | 0.32% |
| Black or African American | 1 | 0.03% |
| Asian | 1 | 0.03% |
Lyman County 's average per capita income is $48,693. Household income levels show a median of $67,143. The poverty rate stands at 23.65%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $104,833 | - |
| Families | $82,946 | $123,410 |
| Households | $67,143 | $99,810 |
| Non Families | $43,295 | $51,580 |
Average Income
Median Household Income
Poverty Rate