Castro County leans heavily Republican by roughly 40 points: about 30% of voters vote Democratic and 70% Republican.
About 56% of adults in Castro County typically vote, below the U.S. average of about 62%. Among adults in Castro County, ~17% vote Democratic, ~39% Republican, and ~44% don't vote. The map below shows estimated turnout by block group.
How Castro County compares
Among counties within 50 miles, Castro County leans more Republican than 1 of 7 neighbors.
Castro County runs about 27 points more Republican than Texas as a whole.
Politics vary noticeably by city within Castro County. The northeast side is the most Republican-leaning (R+77) and the north side is the least Republican-leaning (R+25), a spread of about 52 points.
Why Castro County leans the way it does
This analysis examined 14,881 data points per county to find what predicts political lean and turnout. The items below are a few correlations that stood out for Castro County, not a ranked or complete list of what matters most.
Areas with many family households vote Republican. About 79% of households in Castro County are family households, about 13 points above the U.S. average of 67%. Rural areas vote Republican, and Castro County sits in the bottom quarter on density (about 9%, below 85% of counties).
Preventive-care access and voter turnout
Places with limited routine preventive-care access tend to turn out at a lower rate; Castro County, TX sits in the bottom quarter nationally on this measure. Dental visits do not drive turnout; the rate reflects income, insurance, and healthcare access, which line up with who votes.
Why turnout in Castro County looks the way it does
Areas with limited routine healthcare access turn out at lower rates. Castro County is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The uninsured rate here is about 28%, about 9 points above the Texas average of 19%. Renters vote less often than owners, and about 35% of households in Castro County rent, above 86% of counties. Low high-school completion lines up with lower turnout, and about 73% of adults in Castro County have completed high school, in the bottom fraction of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Deaf Smith County, TX R+30
- Swisher County, TX R+48
- Parmer County, TX R+50
- Bailey County, TX R+49
- Lamb County, TX R+57
- Hale County, TX R+44
- Randall County, TX R+46
- Oldham County, TX R+80
- Potter County, TX R+19
- Curry County, NM R+34
Counties with Similar Populations
- Elliott County, KY R+57
- Grant County, KS R+59
- Wallowa County, OR R+20
- Rappahannock County, VA R+17
- Lee County, KY R+67
- Gilmer County, WV R+40
- Chariton County, MO R+61
- Lexington City, VA D+10
- Pepin County, WI R+30
- Pierce County, NE R+72
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.