Delaware County leans heavily Republican by roughly 38 points: about 31% of voters vote Democratic and 69% Republican.
About 88% of adults in Delaware County typically vote, above the U.S. average of about 62%. Among adults in Delaware County, ~27% vote Democratic, ~61% Republican, and ~12% don't vote. The map below shows estimated turnout by block group.
How Delaware County compares
Among counties within 50 miles, Delaware County is the most Republican-leaning.
Delaware County runs about 26 points more Republican than Iowa as a whole.
Politics vary noticeably by city within Delaware County. The northeast side is the most Republican-leaning (R+53) and the west side is the least Republican-leaning (R+30), a spread of about 23 points.
Why Delaware County leans the way it does
Density, race composition, education, and family structure all sit close to their national averages in Delaware County. The lean here lands roughly where demographic data alone would predict.
Cancer-screening access and voter turnout
Places with high colon-cancer-screening access tend to turn out at a higher rate; Delaware County, IA sits in the top quarter nationally on this measure. Cancer screening does not drive turnout; it reflects income, insurance, and healthcare access.
Why turnout in Delaware County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Delaware 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%. Homeowners vote more often than renters, and about 82% of households in Delaware County own their home, above 86% of counties. High high-school completion lines up with higher turnout, and about 94% of adults in Delaware County have completed high school, above 86% of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Jones County, IA R+27
- Buchanan County, IA R+36
- Clayton County, IA R+39
- Dubuque County, IA R+12
- Fayette County, IA R+30
- Linn County, IA D+7
- Benton County, IA R+36
- Grant County, WI R+23
- Jackson County, IA R+35
- Black Hawk County, IA D+3
Counties with Similar Populations
- Lee County, TX R+52
- Northampton County, NC D+15
- Polk County, TN R+72
- Park County, CO R+9
- Pike County, MO R+55
- Patrick County, VA R+58
- Seward County, NE R+52
- Pitkin County, CO D+40
- Hancock County, IL R+45
- Drew County, AR R+25
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.