78840 leans slightly Republican by roughly 12 points: about 44% of voters vote Democratic and 56% Republican.
About 52% of adults in 78840 typically vote, below the U.S. average of about 62%. Among adults in 78840, ~23% vote Democratic, ~29% Republican, and ~48% don't vote. The map below shows estimated turnout by block group.
How 78840 compares
78840 sits in a sparsely populated area with few comparable zip codes nearby.
Politically, 78840 sits close to the rest of Texas.
Politics vary noticeably by block within 78840. The northeast side is the most Republican-leaning (R+48) and the south side is the least Republican-leaning (R+3), a spread of about 45 points.
Why 78840 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 78840, not a ranked or complete list of what matters most.
78840 votes Republican even though it is densely developed (about 69%, far above the Texas average of 35%). State and regional patterns outweigh the Democratic lean that density usually predicts here.
Cancer-screening access and voter turnout
Places with low colon-cancer-screening access tend to turn out at a lower rate; 78840, 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 78840 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 78840 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%. Low high-school completion lines up with lower turnout, and about 76% of adults in 78840 have completed high school, below 95% 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.