51020 is a Republican stronghold. About 17% of voters here vote Democratic and 83% Republican.
About 78% of adults in 51020 typically vote, above the U.S. average of about 62%. Among adults in 51020, ~13% vote Democratic, ~65% Republican, and ~22% don't vote. The map below shows estimated turnout by block group.
How 51020 compares
Among zip codes within 15 miles, 51020 is the most Republican-leaning.
51020 runs about 53 points more Republican than Iowa as a whole.
Politics vary noticeably by block within 51020. The west side is the most Republican-leaning (R+69) and the northeast side is the least Republican-leaning (R+55), a spread of about 14 points.
Why 51020 leans the way it does
Density, race composition, education, and family structure all sit close to their national averages in 51020. The lean here lands roughly where demographic data alone would predict.
Population density and Republican lean
Places with low population density tend to lean Republican; 51020, IA sits in the bottom quarter nationally on this measure.
Why turnout in 51020 looks the way it does
Areas with high high-school completion turn out at higher rates. About 96% of adults in 51020 have completed high school, about 6 points above the U.S. average of 90%. 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.