79121 leans heavily Republican by roughly 36 points: about 32% of voters vote Democratic and 68% Republican.
About 74% of adults in 79121 typically vote, above the U.S. average of about 62%. Among adults in 79121, ~24% vote Democratic, ~50% Republican, and ~26% don't vote. The map below shows estimated turnout by block group.
How 79121 compares
Among zip codes within 15 miles, 79121 leans more Republican than 7 of 16 neighbors.
79121 runs about 22 points more Republican than Texas as a whole.
Politics vary noticeably by block within 79121. The northwest side is the most Republican-leaning (R+47) and the east side is the least Republican-leaning (R+29), a spread of about 18 points.
Why 79121 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 79121, not a ranked or complete list of what matters most.
79121 votes Republican even though it is densely developed (about 99%, far above the Texas average of 35%). Here an older population outweighs the Democratic lean that density usually predicts.
High-school completion and voter turnout
Places with high-school-completion-heavy adults tend to turn out at a higher rate; 79121, TX sits in the top tenth nationally on this measure.
Why turnout in 79121 looks the way it does
Areas with high high-school completion turn out at higher rates. About 98% of adults in 79121 have completed high school, about 12 points above the Texas average of 86%. 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.