57658 is a Democratic stronghold. About 81% of voters here vote Democratic and 19% Republican.
About 51% of adults in 57658 typically vote, below the U.S. average of about 62%. Among adults in 57658, ~41% vote Democratic, ~10% Republican, and ~49% don't vote. The map below shows estimated turnout by block group.
How 57658 compares
Among zip codes within 15 miles, 57658 is the most Democratic-leaning.
57658 runs about 91 points more Democratic than South Dakota as a whole. South Dakota leans Republican overall, while 57658 is one of the few Democratic-leaning pockets.
Why 57658 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 57658, not a ranked or complete list of what matters most.
57658 votes against the grain of South Dakota. South Dakota leans Republican overall, while 57658 runs about 91 points more Democratic. A high never-married share predicts Democratic voting, and about 58% of adults in 57658 have never been married, above 98% of zip codes.
Cancer-screening access and voter turnout
Places with low colon-cancer-screening access tend to turn out at a lower rate; 57658, 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 57658 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 57658 is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 46%, about 19 points below the South Dakota average of 66%. Renters vote less often than owners, and about 43% of households in 57658 rent, about 18 points above the U.S. average of 25%. High-crime urban areas turn out at lower rates, and 57658 sits in the top 15% on a violent-crime measure. 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.