63304 leans Republican by roughly 16 points: about 42% of voters vote Democratic and 58% Republican.
About 82% of adults in 63304 typically vote, above the U.S. average of about 62%. Among adults in 63304, ~34% vote Democratic, ~48% Republican, and ~18% don't vote. The map below shows estimated turnout by block group.
How 63304 compares
Among zip codes within 15 miles, 63304 leans more Republican than 21 of 29 neighbors.
Politically, 63304 sits close to the rest of Missouri.
Politics vary noticeably by block within 63304. The south side is the most Republican-leaning (R+24) and the east side is the least Republican-leaning (R+10), a spread of about 14 points.
Why 63304 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 63304, not a ranked or complete list of what matters most.
63304 votes Republican even though it is densely developed (about 81%, far above the Missouri average of 22%). State and regional patterns outweigh the Democratic lean that density usually predicts here. A high family-household share predicts Republican voting, and about 77% of households in 63304 are family households, above 85% of zip codes.
High-school completion, uninsured rate, and voter turnout
Places that combine high-school-completion-heavy adults and a low uninsured rate tend to turn out at a higher rate, as 63304, MO does.
Why turnout in 63304 looks the way it does
Areas with strong routine healthcare access turn out at higher rates. 63304 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 69%, about 9 points above the U.S. average of 60%. High high-school completion lines up with higher turnout, and about 97% of adults in 63304 have completed high school, above 90% of zip codes. 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.