McCook County is a Republican stronghold. About 23% of voters here vote Democratic and 77% Republican.
About 74% of adults in McCook County typically vote, above the U.S. average of about 62%. Among adults in McCook County, ~17% vote Democratic, ~57% Republican, and ~26% don't vote. The map below shows estimated turnout by block group.
How McCook County compares
Among counties within 50 miles, McCook County leans more Republican than 8 of 11 neighbors.
McCook County runs about 25 points more Republican than South Dakota as a whole.
Why McCook 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 McCook County, not a ranked or complete list of what matters most.
Rural areas with a high white share vote Republican. McCook County sits in the bottom quarter on density and about 93% of residents are non-Hispanic white, about 12 points above the South Dakota average of 81%. A high family-household share predicts Republican voting, and about 70% of households in McCook County are family households, above 80% of counties.
Preventive-care access and voter turnout
Places with strong routine preventive-care access tend to turn out at a higher rate; McCook 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 McCook County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. McCook 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 70%, about 10 points above the U.S. average of 60%. High high-school completion lines up with higher turnout, and about 95% of adults in McCook County have completed high school, above 88% of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Hanson County, SD R+72
- Miner County, SD R+52
- Lake County, SD R+38
- Turner County, SD R+53
- Hutchinson County, SD R+65
- Minnehaha County, SD R+10
- Lincoln County, SD R+29
- Davison County, SD R+43
- Moody County, SD R+40
- Sanborn County, SD R+59
Counties with Similar Populations
- Lincoln County, CO R+61
- Audubon County, IA R+46
- Alfalfa County, OK R+76
- Ransom County, ND R+46
- Gray County, KS R+73
- Bent County, CO R+29
- Lincoln County, MN R+49
- Putnam County, IL R+28
- San Saba County, TX R+68
- Talbot County, GA D+12
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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.