Union County leans heavily Republican by roughly 34 points: about 33% of voters vote Democratic and 67% Republican.
About 90% of adults in Union County typically vote, above the U.S. average of about 62%. Among adults in Union County, ~30% vote Democratic, ~60% Republican, and ~10% don't vote. The map below shows estimated turnout by block group.
How Union County compares
Among counties within 50 miles, Union County leans more Republican than 2 of 13 neighbors.
Union County runs about 20 points more Republican than Iowa as a whole.
Politics vary noticeably by city within Union County. The south side is the most Republican-leaning (R+50) and the northwest side is the least Republican-leaning (R+24), a spread of about 26 points.
Why Union County leans the way it does
Density, race composition, education, and family structure all sit close to their national averages in Union County. The lean here lands roughly where demographic data alone would predict.
High-school completion, uninsured rate, and voter turnout
Places that combine high-school-completion-heavy adults and a low uninsured rate tend to turn out at a higher rate, as Union County, IA does.
Why turnout in Union County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Union 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 68%, about 8 points above the U.S. average of 60%. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Adams County, IA R+46
- Adair County, IA R+46
- Ringgold County, IA R+50
- Madison County, IA R+41
- Clarke County, IA R+41
- Taylor County, IA R+50
- Decatur County, IA R+44
- Worth County, MO R+64
- Cass County, IA R+41
- Guthrie County, IA R+41
Counties with Similar Populations
- Crawford County, GA R+48
- Glades County, FL R+47
- Edmonson County, KY R+67
- Rains County, TX R+75
- Blackford County, IN R+49
- Lake County, MI R+30
- Morrow County, OR R+36
- Rolette County, ND D+33
- Jefferson County, MT R+38
- Macon County, GA D+22
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.