Thomas is a Republican stronghold. About 11% of voters here vote Democratic and 89% Republican.
About 79% of adults in Thomas typically vote, above the U.S. average of about 62%. Among adults in Thomas, ~9% vote Democratic, ~70% Republican, and ~21% don't vote. The map below shows estimated turnout by block group.
How Thomas compares
Among cities within 25 miles, Thomas is the most Republican-leaning.
Thomas runs about 49 points more Republican than South Dakota as a whole.
Why Thomas leans the way it does
This analysis examined 14,881 data points per city to find what predicts political lean and turnout. The items below are a few correlations that stood out for Thomas, not a ranked or complete list of what matters most.
Rural areas with a high white share vote Republican. Thomas sits in the bottom quarter on density and more than 99% of residents are non-Hispanic white, about 19 points above the South Dakota average of 81%. A high family-household share predicts Republican voting, and about 79% of households in Thomas are family households, above 88% of cities.
Park access and Republican lean
Places with low park coverage tend to lean Republican; Thomas, SD sits in the bottom tenth nationally on this measure. Park access does not change how people vote; it tends to track denser, higher-income areas.
Why turnout in Thomas looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Thomas 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 69%, about 9 points above the U.S. average of 60%. High high-school completion lines up with higher turnout, and about 96% of adults in Thomas have completed high school, above 83% of cities. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Grover, SD R+66
- Kones Corner, SD R+65
- Hayti, SD R+73
- Foley, SD R+54
- Hazel, SD R+74
- Kampeska, SD R+57
- Castlewood, SD R+56
- Watertown, SD R+40
- Lake Norden, SD R+70
- Stone Bridge, SD R+50
Cities with Similar Populations
- Sardis, WV R+61
- Mackay, TX R+37
- Zortman, MT R+59
- Tecate, CA R+14
- Newgulf, TX R+54
- Wabash, NE R+45
- Grimes, OK R+83
- Smith, KY R+81
- Sea Island, GA R+37
- Wakefield, TX R+69
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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.