Sioux Center leans heavily Republican by roughly 48 points: about 26% of voters vote Democratic and 74% Republican.
About 95% of adults in Sioux Center typically vote, above the U.S. average of about 62%. Among adults in Sioux Center, ~25% vote Democratic, ~70% Republican, and ~5% don't vote. The map below shows estimated turnout by block group.
How Sioux Center compares
Among cities within 25 miles, Sioux Center leans more Republican than 5 of 38 neighbors.
Sioux Center runs about 34 points more Republican than Iowa as a whole.
Politics vary noticeably by neighborhood within Sioux Center. The southwest side is the most Republican-leaning (R+72) and the north side is the least Republican-leaning (R+38), a spread of about 35 points.
Why Sioux Center 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 Sioux Center, not a ranked or complete list of what matters most.
Sioux Center votes Republican even though it is densely developed (about 57%, far above the Iowa average of 16%). State and regional patterns outweigh the Democratic lean that density usually predicts here.
Park access and Republican lean
Places with low park coverage tend to lean Republican; Sioux Center, IA sits in the bottom quarter nationally on this measure. Park access does not change how people vote; it tends to track denser, higher-income areas.
Why turnout in Sioux Center looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Sioux Center 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 70%, about 10 points above the U.S. average of 60%. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Perkins, IA R+75
- Orange City, IA R+41
- Maurice, IA R+71
- Hull, IA R+71
- Ireton, IA R+78
- Newkirk, IA R+72
- Rock Valley, IA R+62
- Carnes, IA R+52
- Alton, IA R+54
- Boyden, IA R+72
Cities with Similar Populations
- Valdese, NC R+43
- New Richmond, OH R+50
- Golden Hills, CA R+37
- Ayden, NC R+8
- Toronto, OH R+45
- Springfield, GA R+38
- Bonadelle Ranchos-Madera Ranchos, CA R+37
- Madison, FL D+5
- Harahan, LA R+29
- Bel Aire, KS R+10
Sources and methodology
Precinct-level voting records used to fit the model come from Iowa 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.