63103 is a Democratic stronghold. About 87% of voters here vote Democratic and 13% Republican.
About 40% of adults in 63103 typically vote, below the U.S. average of about 62%. Among adults in 63103, ~35% vote Democratic, ~5% Republican, and ~60% don't vote. The map below shows estimated turnout by block group.
How 63103 compares
Among zip codes within 15 miles, 63103 leans more Democratic than 52 of 71 neighbors.
63103 runs about 92 points more Democratic than Missouri as a whole. Missouri leans Republican overall, while 63103 is one of the few Democratic-leaning pockets.
Politics vary noticeably by block within 63103. The northwest side is the most Democratic-leaning (D+80) and the northeast side is the least Democratic-leaning (D+64), a spread of about 16 points.
Why 63103 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 63103, not a ranked or complete list of what matters most.
Dense areas vote Democratic. More than 99% of residents in 63103 live in densely developed areas, about 64 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and 63103 sits in the top quarter (about 46%, above 86% of zip codes). 63103 runs against the grain of Missouri, a Democratic-leaning pocket in a Republican-leaning state.
Paved land cover and Democratic lean
Places with extensive paved surfaces tend to lean Democratic; 63103, MO sits in the top tenth nationally on this measure. Paved ground does not change how people vote; it mostly reflects how urban and built-up a place is.
Why turnout in 63103 looks the way it does
Renters vote less often than owners. About 84% of households in 63103 rent, about 59 points above the U.S. average of 25%. High food insecurity lines up with lower turnout, and about 26% of adults in 63103 report food insecurity, above 90% of zip codes. High-crime urban areas turn out at lower rates, and 63103 sits in the top 15% on a violent-crime measure. 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 Missouri 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.