57521 leans heavily Republican by roughly 42 points: about 29% of voters vote Democratic and 71% Republican.
About 46% of adults in 57521 typically vote, below the U.S. average of about 62%. Among adults in 57521, ~13% vote Democratic, ~32% Republican, and ~55% don't vote. The map below shows estimated turnout by block group.
How 57521 compares
57521 runs about 12 points more Republican than South Dakota as a whole.
Politics vary noticeably by block within 57521. The west side is the most Republican-leaning (R+73) and the east side is the least Republican-leaning (R+12), a spread of about 62 points.
Why 57521 leans the way it does
Density, race composition, education, and family structure all sit close to their national averages in 57521. The lean here lands roughly where demographic data alone would predict.
Paved land cover and Republican lean
Places with little paved surface tend to lean Republican; 57521, SD sits in the bottom tenth nationally on this measure. Paved ground does not change how people vote; it mostly reflects how urban and built-up a place is.
Why turnout in 57521 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 57521 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 57521 rent, above 86% of zip codes. Low high-school completion lines up with lower turnout, and about 86% of adults in 57521 have completed high school, below 77% 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.