Dewey County, South Dakota Demographics 2026

Population Overview

Dewey County is located in South Dakota with a total population of 5,205. It is the 36th most populous county out of 66 in South Dakota. The county encompasses 9 Census-designated places.

Age Demographics

The median age in Dewey County is 27.7 years. This is 27% lower than the state median of 38.0 years. With 38.4% of the population under 18, Dewey County has a notably young demographic profile, suggesting a family-oriented community.

Economy, Income & Housing

The median household income in Dewey County is $54,104. This is 28% lower than the state median of $75,081. It is also 33% lower than the national median of $80,734. The poverty rate stands at 33.0%. This is 177% higher than the state poverty rate of 11.9%. With more than one in five residents living below the poverty line, economic hardship is a significant challenge for the community. The unemployment rate is 13.9%. This is 375% higher than the state rate of 2.9%. The median home value is $69,600. Housing costs are 73% lower than the state median of $257,400. With a home-value-to-income ratio of just 1.3x, Dewey County is one of the most affordable housing markets in the area. 61.2% of occupied housing units are owner-occupied. This homeownership rate is 11% lower than the state average of 68.6%.

Race & Ethnicity

Dewey County is a highly diverse community where no single racial or ethnic group constitutes a majority of the population. Hispanic or Latino residents account for 1.0%. The White (non-Hispanic) population (21.0%) is well below the state average of 79.8%. The Black or African American population (0.5%) is well below the state average of 2.1%. The Hispanic or Latino population (1.0%) is well below the state average of 4.8%. The Asian population (0.1%) is well below the state average of 1.4%.

Education

18.8% of residents aged 25 and older hold a bachelor's degree or higher. This is 41% lower than the state rate of 31.9%. Nationally, 35.7% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 86.7%.

Data Sources & Methodology

All figures for Dewey County come from the U.S. Census Bureau's American Community Survey (ACS) 2020–2024 5-Year Estimates, with comparisons drawn against South Dakota and national averages from the same dataset. See our methodology page for how each metric is defined, or data.census.gov for official tables with margins of error.