78102 leans Republican by roughly 18 points: about 41% of voters vote Democratic and 59% Republican.
About 52% of adults in 78102 typically vote, below the U.S. average of about 62%. Among adults in 78102, ~21% vote Democratic, ~31% Republican, and ~48% don't vote. The map below shows estimated turnout by block group.
How 78102 compares
Among zip codes within 15 miles, 78102 is the least Republican-leaning.
78102 runs about 5 points more Republican than Texas as a whole.
Politics vary noticeably by block within 78102. The northwest side is the most Republican-leaning (R+48) and the southeast side is the least Republican-leaning (R+5), a spread of about 43 points.
Why 78102 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 78102, not a ranked or complete list of what matters most.
Car-dependent areas vote Republican. About 83% of residents in 78102 drive to work alone, about 9 points above the U.S. average of 74%. Low college attainment predicts Republican voting, and 78102 sits in the bottom quarter (about 14%, below 85% of zip codes).
Cancer-screening access and voter turnout
Places with low colon-cancer-screening access tend to turn out at a lower rate; 78102, TX sits in the bottom tenth nationally on this measure. Cancer screening does not drive turnout; it reflects income, insurance, and healthcare access.
Why turnout in 78102 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 78102 is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 47%, about 7 points below the Texas average of 54%. Low high-school completion lines up with lower turnout, and about 81% of adults in 78102 have completed high school, below 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.