57657 leans slightly Democratic by roughly 12 points: about 56% of voters vote Democratic and 44% Republican.
About 44% of adults in 57657 typically vote, below the U.S. average of about 62%. Among adults in 57657, ~25% vote Democratic, ~19% Republican, and ~56% don't vote. The map below shows estimated turnout by block group.
How 57657 compares
Among zip codes within 15 miles, 57657 leans more Democratic than 3 of 4 neighbors.
57657 runs about 41 points more Democratic than South Dakota as a whole. South Dakota leans Republican overall, while 57657 is one of the few Democratic-leaning pockets.
Politics vary noticeably by block within 57657. The north side runs the most Democratic (D+58) and the southwest side runs the most Republican (R+51), a spread of about 109 points.
Why 57657 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 57657, not a ranked or complete list of what matters most.
57657 votes against the grain of South Dakota. South Dakota leans Republican overall, while 57657 runs about 41 points more Democratic. A high never-married share predicts Democratic voting, and about 40% of adults in 57657 have never been married, above 88% of zip codes.
Cancer-screening access and voter turnout
Places with low colon-cancer-screening access tend to turn out at a lower rate; 57657, SD sits in the bottom tenth nationally on this measure. Cancer screening does not drive turnout; it reflects income, insurance, and healthcare access.
Why turnout in 57657 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 57657 is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. Renters vote less often than owners, and about 39% of households in 57657 rent, above 86% of 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.