Tehama County leans heavily Republican by roughly 34 points: about 33% of voters vote Democratic and 67% Republican.
About 60% of adults in Tehama County typically vote, near the U.S. average of about 62%. Among adults in Tehama County, ~20% vote Democratic, ~40% Republican, and ~40% don't vote. The map below shows estimated turnout by block group.
How Tehama County compares
Among counties within 50 miles, Tehama County is the most Republican-leaning.
Tehama County runs about 55 points more Republican than California as a whole. California leans Democratic overall, while Tehama County is one of the few Republican-leaning pockets.
Politics vary noticeably by city within Tehama County. The southeast side is the most Republican-leaning (R+49) and the south side is the least Republican-leaning (R+28), a spread of about 22 points.
Why Tehama 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 Tehama County, not a ranked or complete list of what matters most.
Tehama County votes against the grain of California. California leans Democratic overall, while Tehama County runs about 55 points more Republican.
Cancer-screening access and voter turnout
Places with low colon-cancer-screening access tend to turn out at a lower rate; Tehama County, CA sits in the bottom quarter nationally on this measure. Cancer screening does not drive turnout; it reflects income, insurance, and healthcare access.
Why turnout in Tehama County looks the way it does
Crowded housing lines up with lower turnout. About 5% of homes in Tehama County have more than one occupant per room, above 92% of counties. Renters vote less often than owners, and about 32% of households in Tehama County rent, above 81% of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Glenn County, CA R+32
- Shasta County, CA R+30
- Butte County, CA R+3
- Trinity County, CA R+14
- Colusa County, CA R+20
- Sutter County, CA R+23
- Plumas County, CA R+23
- Yuba County, CA R+16
- Lake County, CA R+4
- Mendocino County, CA D+23
Counties with Similar Populations
- Sauk County, WI R+20
- Starr County, TX R+7
- Warren County, NY R+2
- Adams County, IL R+40
- Harrison County, WV R+41
- Mason County, WA R+5
- Wilkes County, NC R+57
- Marquette County, MI Even
- Apache County, AZ D+30
- Armstrong County, PA R+52
All Local Stats
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Sources and methodology
Precinct-level voting records used to fit the model come from California Secretary of State, Elections, 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.