78631 is a Republican stronghold. About 13% of voters here vote Democratic and 87% Republican.
About 81% of adults in 78631 typically vote, above the U.S. average of about 62%. Among adults in 78631, ~11% vote Democratic, ~70% Republican, and ~19% don't vote. The map below shows estimated turnout by block group.
How 78631 compares
Among zip codes within 15 miles, 78631 is the most Republican-leaning.
78631 runs about 60 points more Republican than Texas as a whole.
Why 78631 leans the way it does
Density, race composition, education, and family structure all sit close to their national averages in 78631. 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; 78631, TX sits in the bottom quarter nationally on this measure.
Why turnout in 78631 looks the way it does
Turnout in 78631 sits close to the national pattern. Routine healthcare access, homeownership, education, and food security all land near their national averages here. 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.