Cass County leans heavily Republican by roughly 42 points: about 29% of voters vote Democratic and 71% Republican.
About 94% of adults in Cass County typically vote, above the U.S. average of about 62%. Among adults in Cass County, ~27% vote Democratic, ~67% Republican, and ~6% don't vote. The map below shows estimated turnout by block group.
How Cass County compares
Among counties within 50 miles, Cass County leans more Republican than 7 of 14 neighbors.
Cass County runs about 28 points more Republican than Iowa as a whole.
Politics vary noticeably by city within Cass County. The southeast side is the most Republican-leaning (R+59) and the west side is the least Republican-leaning (R+37), a spread of about 22 points.
Why Cass County leans the way it does
Density, race composition, education, and family structure all sit close to their national averages in Cass County. The lean here lands roughly where demographic data alone would predict.
Preventive-care access and voter turnout
Places with strong routine preventive-care access tend to turn out at a higher rate; Cass 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 Cass County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Cass 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 66%, about 6 points above the U.S. average of 60%. High high-school completion lines up with higher turnout, and about 94% of adults in Cass County have completed high school, above 88% of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Audubon County, IA R+46
- Adair County, IA R+46
- Montgomery County, IA R+41
- Shelby County, IA R+48
- Adams County, IA R+46
- Guthrie County, IA R+41
- Union County, IA R+33
- Pottawattamie County, IA R+18
- Mills County, IA R+33
- Page County, IA R+39
Counties with Similar Populations
- Powell County, KY R+60
- Big Horn County, MT Even
- Kodiak Island Borough, AK R+16
- Mason County, IL R+46
- Shoshone County, ID R+43
- Lewis County, KY R+66
- Crenshaw County, AL R+54
- Mono County, CA D+13
- Lamb County, TX R+57
- Cass County, IL R+31
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.