50311 leans heavily Democratic by roughly 46 points: about 73% of voters vote Democratic and 27% Republican.
About 61% of adults in 50311 typically vote, near the U.S. average of about 62%. Among adults in 50311, ~45% vote Democratic, ~16% Republican, and ~39% don't vote. The map below shows estimated turnout by block group.
How 50311 compares
Among zip codes within 15 miles, 50311 leans more Democratic than 30 of 33 neighbors.
50311 runs about 59 points more Democratic than Iowa as a whole. Iowa leans Republican overall, while 50311 is one of the few Democratic-leaning pockets.
Politics vary noticeably by block within 50311. The south side is the most Democratic-leaning (D+61) and the northwest side is the least Democratic-leaning (D+29), a spread of about 31 points.
Why 50311 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 50311, not a ranked or complete list of what matters most.
Dense areas vote Democratic. More than 99% of residents in 50311 live in densely developed areas, about 63 points above the U.S. average of 36%. A high never-married share predicts Democratic voting, and about 55% of adults in 50311 have never been married, above 97% of zip codes. 50311 runs against the grain of Iowa, a Democratic-leaning pocket in a Republican-leaning state.
Population density and Democratic lean
Places with high population density tend to lean Democratic; 50311, IA sits in the top tenth nationally on this measure.
Why turnout in 50311 looks the way it does
Renters vote less often than owners. About 49% of households in 50311 rent, about 24 points above the U.S. average of 25%. 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.