Story County leans slightly Democratic by roughly 14 points: about 57% of voters vote Democratic and 43% Republican.
About 75% of adults in Story County typically vote, above the U.S. average of about 62%. Among adults in Story County, ~43% vote Democratic, ~32% Republican, and ~25% don't vote. The map below shows estimated turnout by block group.
How Story County compares
Among counties within 50 miles, Story County is the most Democratic-leaning.
Story County runs about 27 points more Democratic than Iowa as a whole. Iowa leans Republican overall, while Story County is one of the few Democratic-leaning pockets.
Politics vary noticeably by city within Story County. The west side runs the most Democratic (D+30) and the northeast side runs the most Republican (R+34), a spread of about 64 points.
Why Story County leans the way it does
This analysis examined 14,881 data points per county to find what predicts political lean and turnout. The items below are a few correlations that stood out for Story County, not a ranked or complete list of what matters most.
Areas with high college attainment vote Democratic. About 57% of adults in Story County hold a bachelor's degree, about 29 points above the U.S. average of 28%. Dense areas vote Democratic, and Story County sits in the top fifth on density (about 61%, above 86% of counties). A high never-married share predicts Democratic voting, and about 48% of adults in Story County have never been married, in the top fraction of counties.
Population density and Democratic lean
Places with high population density tend to lean Democratic; Story County, IA sits in the top tenth nationally on this measure.
Why turnout in Story County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Story County 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 67%, about 7 points above the U.S. average of 60%. High high-school completion lines up with higher turnout, and about 97% of adults in Story County have completed high school, in the top fraction of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Boone County, IA R+24
- Polk County, IA D+12
- Hamilton County, IA R+34
- Dallas County, IA R+7
- Marshall County, IA R+17
- Hardin County, IA R+40
- Jasper County, IA R+28
- Greene County, IA R+39
- Warren County, IA R+24
- Webster County, IA R+22
Counties with Similar Populations
- Floyd County, GA R+37
- Burleigh County, ND R+32
- Sevier County, TN R+58
- Madison County, TN R+2
- Grant County, WA R+34
- Portsmouth City, VA D+41
- Dubuque County, IA R+12
- Putnam County, NY R+13
- Lenawee County, MI R+27
- Marshall County, AL R+64
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.