78731 leans heavily Democratic by roughly 40 points: about 70% of voters vote Democratic and 30% Republican.
About 81% of adults in 78731 typically vote, above the U.S. average of about 62%. Among adults in 78731, ~57% vote Democratic, ~24% Republican, and ~19% don't vote. The map below shows estimated turnout by block group.
How 78731 compares
Among zip codes within 15 miles, 78731 leans more Democratic than 28 of 47 neighbors.
78731 runs about 54 points more Democratic than Texas as a whole. Texas leans Republican overall, while 78731 is one of the few Democratic-leaning pockets.
Politics vary noticeably by block within 78731. The northeast side is the most Democratic-leaning (D+61) and the southwest side is the least Democratic-leaning (D+11), a spread of about 51 points.
Why 78731 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 78731, not a ranked or complete list of what matters most.
Areas with high college attainment vote Democratic. About 78% of adults in 78731 hold a bachelor's degree, about 50 points above the U.S. average of 28%. Dense areas vote Democratic, and 78731 sits in the top fifth on density (about 87%, above 86% of zip codes). 78731 runs against the grain of Texas, a Democratic-leaning pocket in a Republican-leaning state.
Walkability and Democratic lean
Places with a highly walkable street grid tend to lean Democratic; 78731, TX sits in the top quarter nationally on this measure. A walkable street grid does not change how people vote; it mostly reflects how urban a place is.
Why turnout in 78731 looks the way it does
Areas with strong routine healthcare access turn out at higher rates. 78731 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 72%, about 12 points above the U.S. average of 60%. High high-school completion lines up with higher turnout, and about 99% of adults in 78731 have completed high school, above 97% 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 Texas Secretary of State, Elections Division, 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.