Brown County leans heavily Republican by roughly 36 points: about 32% of voters vote Democratic and 68% Republican.
About 71% of adults in Brown County typically vote, above the U.S. average of about 62%. Among adults in Brown County, ~23% vote Democratic, ~48% Republican, and ~29% don't vote. The map below shows estimated turnout by block group.
How Brown County compares
Among counties within 50 miles, Brown County leans more Republican than 1 of 7 neighbors.
Brown County runs about 6 points more Republican than South Dakota as a whole.
Politics vary noticeably by city within Brown County. The northeast side is the most Republican-leaning (R+58) and the west side is the least Republican-leaning (R+31), a spread of about 27 points.
Why Brown 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 Brown County, not a ranked or complete list of what matters most.
Brown County votes Republican even though it is densely developed (about 61%, far above the South Dakota average of 9%). State and regional patterns outweigh the Democratic lean that density usually predicts here.
Preventive-care access and voter turnout
Places with strong routine preventive-care access tend to turn out at a higher rate; Brown 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 Brown County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Brown 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%. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Edmunds County, SD R+60
- Spink County, SD R+50
- Faulk County, SD R+66
- Dickey County, ND R+55
- McPherson County, SD R+66
- Marshall County, SD R+31
- Day County, SD R+42
- Clark County, SD R+57
- Sargent County, ND R+50
- LaMoure County, ND R+57
Counties with Similar Populations
- Defiance County, OH R+43
- Susquehanna County, PA R+45
- Guernsey County, OH R+50
- Dallas County, AL D+38
- Woodford County, IL R+40
- Finney County, KS R+25
- Brown County, TX R+58
- Graham County, AZ R+39
- Pontotoc County, OK R+44
- Scott County, MO R+43
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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.