Colusa County leans Republican by roughly 20 points: about 40% of voters vote Democratic and 60% Republican.
About 49% of adults in Colusa County typically vote, below the U.S. average of about 62%. Among adults in Colusa County, ~20% vote Democratic, ~29% Republican, and ~51% don't vote. The map below shows estimated turnout by block group.
How Colusa County compares
Among counties within 50 miles, Colusa County leans more Republican than 4 of 6 neighbors.
Colusa County runs about 41 points more Republican than California as a whole. California leans Democratic overall, while Colusa County is one of the few Republican-leaning pockets.
Politics vary noticeably by city within Colusa County. The west side runs the most Democratic (D+5) and the north side runs the most Republican (R+46), a spread of about 52 points.
Why Colusa 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 Colusa County, not a ranked or complete list of what matters most.
Colusa County votes against the grain of California. California leans Democratic overall, while Colusa County runs about 41 points more Republican. Low college attainment predicts Republican voting, and Colusa County sits in the bottom quarter (about 16%, below 82% of counties). A high family-household share predicts Republican voting, and about 72% of households in Colusa County are family households, above 86% of counties.
Cancer-screening access and voter turnout
Places with low colon-cancer-screening access tend to turn out at a lower rate; Colusa County, CA 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 Colusa County looks the way it does
Areas with limited routine healthcare access turn out at lower rates. Colusa County is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. Renters vote less often than owners, and about 38% of households in Colusa County rent, above 92% of counties. High food insecurity lines up with lower turnout, and about 24% of adults in Colusa County report food insecurity, above 87% of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Sutter County, CA R+23
- Yuba County, CA R+16
- Glenn County, CA R+32
- Lake County, CA R+4
- Butte County, CA R+3
- Yolo County, CA D+35
- Placer County, CA R+11
- Sacramento County, CA D+20
- Napa County, CA D+32
- Sonoma County, CA D+42
Counties with Similar Populations
- Prince Edward County, VA D+7
- Scott County, TN R+70
- Tippah County, MS R+61
- Boone County, WV R+62
- Taylor County, FL R+54
- Wyandot County, OH R+53
- Mitchell County, GA R+9
- Henry County, MO R+54
- Seward County, KS R+27
- Randolph County, AL R+59
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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.