50603 leans heavily Republican by roughly 46 points: about 27% of voters vote Democratic and 73% Republican.
About 67% of adults in 50603 typically vote, near the U.S. average of about 62%. Among adults in 50603, ~18% vote Democratic, ~49% Republican, and ~33% don't vote. The map below shows estimated turnout by block group.
How 50603 compares
Among zip codes within 15 miles, 50603 leans more Republican than 3 of 7 neighbors.
50603 runs about 32 points more Republican than Iowa as a whole.
Why 50603 leans the way it does
This analysis examined 14,881 data points per zip code to find what predicts political lean and turnout. The items below are a few correlations that stood out for 50603, not a ranked or complete list of what matters most.
Areas with a high white share and below-average college attainment vote Republican. In 50603, about 96% of residents are non-Hispanic white, about 24 points above the U.S. average of 72%; about 18% of adults hold a bachelor's degree, about 7 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; 50603, IA sits above the national average 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 50603 looks the way it does
Turnout in 50603 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 Zip Codes
Zip Codes with Similar Populations
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.