Custer County is a Republican stronghold. About 24% of voters here vote Democratic and 76% Republican.
About 65% of adults in Custer County typically vote, near the U.S. average of about 62%. Among adults in Custer County, ~16% vote Democratic, ~49% Republican, and ~35% don't vote. The map below shows estimated turnout by block group.
How Custer County compares
Among counties within 50 miles, Custer County leans more Republican than 3 of 4 neighbors.
Custer County runs about 23 points more Republican than South Dakota as a whole.
Why Custer 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 Custer County, not a ranked or complete list of what matters most.
Rural areas vote Republican. About 6% of residents in Custer County live in densely developed areas, about 30 points below the U.S. average of 36%. A high family-household share predicts Republican voting, and about 70% of households in Custer County are family households, above 78% of counties.
Preventive-care access and voter turnout
Places with strong routine preventive-care access tend to turn out at a higher rate; Custer County, SD sits in the top tenth nationally on this measure. Dental visits do not drive turnout; the rate reflects income, insurance, and healthcare access, which line up with who votes.
Why turnout in Custer County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Custer 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 71%, about 11 points above the U.S. average of 60%. Homeowners vote more often than renters, and about 85% of households in Custer County own their home, above 96% of counties. High high-school completion lines up with higher turnout, and about 95% of adults in Custer County have completed high school, above 90% of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Fall River County, SD R+52
- Pennington County, SD R+28
- Meade County, SD R+51
- Weston County, WY R+68
- Lawrence County, SD R+37
- Butte County, SD R+62
- Dawes County, NE R+39
- Crook County, WY R+78
- Niobrara County, WY R+90
- Sheridan County, NE R+68
Counties with Similar Populations
- Tyler County, WV R+61
- Nevada County, AR R+27
- Rosebud County, MT R+20
- Keith County, NE R+60
- Mercer County, ND R+65
- Atkinson County, GA R+57
- Houston County, TN R+64
- Prairie County, AR R+64
- Hickory County, MO R+62
- Coffey County, KS R+58
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.