57055 leans heavily Republican by roughly 46 points: about 27% of voters vote Democratic and 73% Republican.
About 66% of adults in 57055 typically vote, near the U.S. average of about 62%. Among adults in 57055, ~18% vote Democratic, ~48% Republican, and ~34% don't vote. The map below shows estimated turnout by block group.
How 57055 compares
Among zip codes within 15 miles, 57055 leans more Republican than 11 of 17 neighbors.
57055 runs about 16 points more Republican than South Dakota as a whole.
Politics vary noticeably by block within 57055. The north side is the most Republican-leaning (R+54) and the east side is the least Republican-leaning (R+42), a spread of about 12 points.
Why 57055 leans the way it does
This analysis examined 14,881 data points per zip code to find what predicts political lean and turnout. The items below are a few correlations that stood out for 57055, not a ranked or complete list of what matters most.
Areas with many family households vote Republican. About 74% of households in 57055 are family households, about 8 points above the U.S. average of 67%.
Preventive-care access and voter turnout
Places with strong routine preventive-care access tend to turn out at a higher rate; 57055, 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 57055 looks the way it does
Areas with strong routine healthcare access turn out at higher rates. 57055 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 92% of households in 57055 own their home, compared to around 72% in nearby zip codes. Learn more about the findings and methodology on the political spectrum map.
Nearby Zip Codes
Zip Codes with Similar Populations
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.