78633 leans Republican by roughly 26 points: about 37% of voters vote Democratic and 63% Republican.
About 94% of adults in 78633 typically vote, above the U.S. average of about 62%. Among adults in 78633, ~35% vote Democratic, ~59% Republican, and ~6% don't vote. The map below shows estimated turnout by block group.
How 78633 compares
Among zip codes within 15 miles, 78633 leans more Republican than 5 of 8 neighbors.
78633 runs about 12 points more Republican than Texas as a whole.
Politics vary noticeably by block within 78633. The southwest side is the most Republican-leaning (R+36) and the southeast side is the least Republican-leaning (R+15), a spread of about 21 points.
Why 78633 leans the way it does
Density, race composition, education, and family structure all sit close to their national averages in 78633. The lean here lands roughly where demographic data alone would predict.
Cancer-screening access and voter turnout
Places with high colon-cancer-screening access tend to turn out at a higher rate; 78633, TX sits in the top tenth nationally on this measure. Cancer screening does not drive turnout; it reflects income, insurance, and healthcare access.
Why turnout in 78633 looks the way it does
Areas with strong routine healthcare access turn out at higher rates. 78633 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%. Homeowners vote more often than renters, and about 92% of households in 78633 own their home, compared to around 74% in nearby zip codes. High high-school completion lines up with higher turnout, and about 97% of adults in 78633 have completed high school, above 89% 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.