Clarke County leans heavily Republican by roughly 42 points: about 29% of voters vote Democratic and 71% Republican.
About 87% of adults in Clarke County typically vote, above the U.S. average of about 62%. Among adults in Clarke County, ~25% vote Democratic, ~62% Republican, and ~13% don't vote. The map below shows estimated turnout by block group.
How Clarke County compares
Among counties within 50 miles, Clarke County leans more Republican than 6 of 14 neighbors.
Clarke County runs about 28 points more Republican than Iowa as a whole.
Politics vary noticeably by city within Clarke County. The southwest side is the most Republican-leaning (R+57) and the east side is the least Republican-leaning (R+34), a spread of about 23 points.
Why Clarke 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 Clarke County, not a ranked or complete list of what matters most.
Areas with low college attainment vote Republican. About 16% of adults in Clarke County hold a bachelor's degree, about 8 points below the Iowa average of 24%.
Local retail density and voter turnout
Places with dense local retail within a mile tend to turn out at a higher rate; Clarke County, IA sits in the top tenth nationally on this measure. Nearby retail does not change how people vote; it reflects how urban and built-up a place is.
Why turnout in Clarke County looks the way it does
Turnout in Clarke County sits close to the national pattern. Routine healthcare access, homeownership, education, and food security all land near their national averages here. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Decatur County, IA R+44
- Madison County, IA R+41
- Lucas County, IA R+44
- Warren County, IA R+24
- Union County, IA R+33
- Ringgold County, IA R+50
- Wayne County, IA R+56
- Dallas County, IA R+7
- Polk County, IA D+12
- Adair County, IA R+46
Counties with Similar Populations
- West Carroll Parish, LA R+70
- Switzerland County, IN R+63
- McLean County, ND R+51
- Marion County, TX R+49
- Tunica County, MS D+31
- Rock County, MN R+45
- Wayne County, NE R+44
- Grundy County, MO R+57
- Mountrail County, ND R+35
- Martin County, IN R+59
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.