78066 leans heavily Republican by roughly 40 points: about 30% of voters vote Democratic and 70% Republican.
About more than 99% of adults in 78066 typically vote, above the U.S. average of about 62%. Among adults in 78066, ~32% vote Democratic, ~73% Republican, and ~-5% don't vote. The map below shows estimated turnout by block group.
How 78066 compares
Among zip codes within 15 miles, 78066 leans more Republican than 9 of 11 neighbors.
78066 runs about 27 points more Republican than Texas as a whole.
Politics vary noticeably by block within 78066. The west side is the most Republican-leaning (R+51) and the east side is the least Republican-leaning (R+20), a spread of about 31 points.
Why 78066 leans the way it does
Density, race composition, education, and family structure all sit close to their national averages in 78066. The lean here lands roughly where demographic data alone would predict.
Homeownership and voter turnout
Places with homeowner-heavy households tend to turn out at a higher rate; 78066, TX sits in the top tenth nationally on this measure.
Why turnout in 78066 looks the way it does
Homeowners vote more often than renters. About 94% of households in 78066 own their home, about 19 points above the Texas average of 75%. Limited routine healthcare access lines up with lower turnout, and 78066 sits in the bottom quarter on routine-care measures. High high-school completion lines up with higher turnout, and about 98% of adults in 78066 have completed high school, above 93% 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.