Clayton County leans heavily Republican by roughly 38 points: about 31% of voters vote Democratic and 69% Republican.
About 79% of adults in Clayton County typically vote, above the U.S. average of about 62%. Among adults in Clayton County, ~25% vote Democratic, ~54% Republican, and ~21% don't vote. The map below shows estimated turnout by block group.
How Clayton County compares
Among counties within 50 miles, Clayton County leans more Republican than 7 of 8 neighbors.
Clayton County runs about 25 points more Republican than Iowa as a whole.
Politics vary noticeably by city within Clayton County. The south side is the most Republican-leaning (R+49) and the northeast side is the least Republican-leaning (R+29), a spread of about 20 points.
Why Clayton 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 Clayton County, not a ranked or complete list of what matters most.
Areas with a high white share and below-average college attainment vote Republican. In Clayton County, about 95% of residents are non-Hispanic white, about 23 points above the U.S. average of 72%; about 14% of adults hold a bachelor's degree, about 10 points below the Iowa average of 24%.
Preventive-care access and voter turnout
Places with strong routine preventive-care access tend to turn out at a higher rate; Clayton County, IA sits in the top quarter nationally on this measure. Dental visits do not drive turnout; the rate reflects income, insurance, and healthcare access, which line up with who votes.
Why turnout in Clayton County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Clayton 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 64%, above 75% of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Delaware County, IA R+39
- Crawford County, WI R+26
- Fayette County, IA R+30
- Allamakee County, IA R+32
- Grant County, WI R+23
- Dubuque County, IA R+12
- Winneshiek County, IA R+13
- Buchanan County, IA R+36
- Jones County, IA R+27
- Chickasaw County, IA R+40
Counties with Similar Populations
- Lewis County, WV R+57
- Morgan County, WV R+56
- Dallas County, MO R+66
- Holmes County, MS D+60
- Franklin County, AR R+64
- Cooper County, MO R+46
- Chickasaw County, MS R+12
- Falls County, TX R+25
- Mason County, KY R+42
- Mariposa County, CA R+16
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.