77503 leans slightly Republican by roughly 12 points: about 44% of voters vote Democratic and 56% Republican.
About 39% of adults in 77503 typically vote, below the U.S. average of about 62%. Among adults in 77503, ~17% vote Democratic, ~22% Republican, and ~61% don't vote. The map below shows estimated turnout by block group.
How 77503 compares
Among zip codes within 15 miles, 77503 leans more Republican than 42 of 53 neighbors.
Politically, 77503 sits close to the rest of Texas.
Politics vary noticeably by block within 77503. The east side is the most split-leaning (R+24) and the northwest side is the least split-leaning (Even), a spread of about 23 points.
Why 77503 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 77503, not a ranked or complete list of what matters most.
77503 votes Republican even though it is densely developed (more than 99%, far above the Texas average of 35%). State and regional patterns outweigh the Democratic lean that density usually predicts here. Low college attainment predicts Republican voting, and 77503 sits in the bottom quarter (about 12%, below 91% of zip codes). A high family-household share predicts Republican voting, and about 75% of households in 77503 are family households, above 79% of zip codes.
High-school completion, developed land, and voter turnout
Places that combine low high-school-completion share and a heavily developed built environment tend to turn out at a lower rate, as 77503, TX does.
Why turnout in 77503 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 77503 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 48%, about 6 points below the Texas average of 54%. Renters vote less often than owners, and about 46% of households in 77503 rent, about 21 points above the U.S. average of 25%. Low high-school completion lines up with lower turnout, and about 70% of adults in 77503 have completed high school, below 98% 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.