Castroville leans heavily Republican by roughly 34 points: about 33% of voters vote Democratic and 67% Republican.
About 78% of adults in Castroville typically vote, above the U.S. average of about 62%. Among adults in Castroville, ~26% vote Democratic, ~52% Republican, and ~22% don't vote. The map below shows estimated turnout by block group.
How Castroville compares
Among cities within 25 miles, Castroville leans more Republican than 18 of 32 neighbors.
Castroville runs about 20 points more Republican than Texas as a whole.
Politics vary noticeably by neighborhood within Castroville. The northwest side is the most Republican-leaning (R+41) and the northeast side is the least Republican-leaning (R+26), a spread of about 16 points.
Why Castroville leans the way it does
This analysis examined 14,881 data points per city to find what predicts political lean and turnout. The items below are a few correlations that stood out for Castroville, not a ranked or complete list of what matters most.
Areas with many family households vote Republican. About 85% of households in Castroville are family households, about 18 points above the U.S. average of 67%.
Homeownership and voter turnout
Places with homeowner-heavy households tend to turn out at a higher rate; Castroville, TX sits above the national average on this measure.
Why turnout in Castroville looks the way it does
Areas with limited routine healthcare access turn out at lower rates. Castroville is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Lacoste, TX R+26
- Pearson, TX R+46
- Macdona, TX R+15
- Rio Medina, TX R+35
- Quihi, TX R+63
- Atascosa, TX R+10
- Lytle, TX R+27
- Mico, TX R+58
- New Fountain, TX R+61
- Natalia, TX R+28
Cities with Similar Populations
- Mountainside, NJ Even
- Baldwin Harbor, NY D+39
- Monticello, FL R+17
- Wadesboro, NC D+22
- Trinity, TX R+53
- Sunnyvale, TX R+19
- Dormont, PA D+39
- Louisburg, KS R+39
- Tomahawk, WI R+28
- Rocky Face, GA R+65
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.