Lyman County, South Dakota Demographics 2026

Population Overview

Lyman County is located in South Dakota with a total population of 3,724. It is the 43rd most populous county out of 66 in South Dakota. The county encompasses 7 Census-designated places.

Age Demographics

The median age in Lyman County is 36.1 years. This is 5% lower than the state median of 38.0 years. With 28.0% of the population under 18, Lyman County has a notably young demographic profile, suggesting a family-oriented community.

Economy, Income & Housing

The median household income in Lyman County is $67,143. This is 11% lower than the state median of $75,081. It is also 17% lower than the national median of $80,734. The poverty rate stands at 23.6%. This is 98% 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 4.0%. This is 37% higher than the state rate of 2.9%. The median home value is $165,800. Housing costs are 36% lower than the state median of $257,400. With a home-value-to-income ratio of just 2.5x, Lyman County is one of the most affordable housing markets in the area. 70.0% of occupied housing units are owner-occupied. This homeownership rate is 2% higher than the state average of 68.6%.

Race & Ethnicity

The largest racial or ethnic group in Lyman County is White (non-Hispanic), making up 57.1% of the population. Hispanic or Latino residents account for 1.2%. The Black or African American population (0.0%) is well below the state average of 2.1%. The Hispanic or Latino population (1.2%) is well below the state average of 4.8%. The Asian population (0.0%) is well below the state average of 1.4%.

Education

24.6% of residents aged 25 and older hold a bachelor's degree or higher. This is 23% 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 89.4%.

Data Sources & Methodology

All figures for Lyman 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.