Clark County is a Republican stronghold. About 21% of voters here vote Democratic and 79% Republican.
About 65% of adults in Clark County typically vote, near the U.S. average of about 62%. Among adults in Clark County, ~14% vote Democratic, ~51% Republican, and ~35% don't vote. The map below shows estimated turnout by block group.
How Clark County compares
Among counties within 50 miles, Clark County leans more Republican than 5 of 6 neighbors.
Clark County runs about 28 points more Republican than South Dakota as a whole.
Why Clark County leans the way it does
This analysis examined 14,881 data points per county to find what predicts political lean and turnout. The items below are a few correlations that stood out for Clark County, not a ranked or complete list of what matters most.
Rural areas with a high white share vote Republican. Clark County sits in the bottom quarter on density and about 91% of residents are non-Hispanic white, about 11 points above the South Dakota average of 81%.
Population density and Republican lean
Places with low population density tend to lean Republican; Clark County, SD sits in the bottom tenth nationally on this measure.
Why turnout in Clark County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Clark County is in the top quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 66%, about 6 points above the U.S. average of 60%. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Codington County, SD R+42
- Hamlin County, SD R+64
- Kingsbury County, SD R+50
- Spink County, SD R+50
- Day County, SD R+42
- Beadle County, SD R+46
- Deuel County, SD R+54
- Miner County, SD R+52
- Brown County, SD R+35
- Grant County, SD R+52
Counties with Similar Populations
- Sargent County, ND R+50
- Sharkey County, MS D+48
- Chase County, NE R+71
- Haskell County, KS R+66
- Sioux County, ND D+54
- Corson County, SD D+38
- Lake of the Woods County, MN R+40
- Pope County, IL R+60
- Ellis County, OK R+77
- Knox County, MO R+66
All Local Stats
Home Services
Sources and methodology
Precinct-level voting records used to fit the model come from South Dakota Secretary of State, Elections, distributed by the Voting and Election Science Team. Demographic inputs come from the U.S. Census Bureau (ACS 5-year estimates and the 2020 Decennial Census). Health and environmental inputs come from the CDC (PLACES and the Environmental Justice Index). Land cover comes from the USGS and EPA. Election-day and lead-up weather come from PRISM 4km daily grids and the NOAA Global Historical Climatology Network. Mail-voting and election-administration patterns come from the MIT Election Lab's Survey of the Performance of American Elections. Block-group crime detail comes from CrimeGrade. Internet data and modeling support provided by ISPreports.org.
Modeling and analysis by the BestNeighborhood data science team. Full methodology and findings: political spectrum map.
Methodology reviewed by the BestNeighborhood data team. Last updated May 2026.