Napa County leans heavily Democratic by roughly 32 points: about 66% of voters vote Democratic and 34% Republican.
About 64% of adults in Napa County typically vote, near the U.S. average of about 62%. Among adults in Napa County, ~42% vote Democratic, ~22% Republican, and ~36% don't vote. The map below shows estimated turnout by block group.
How Napa County compares
Among counties within 50 miles, Napa County leans more Democratic than 1 of 7 neighbors.
Napa County runs about 11 points more Democratic than California as a whole.
Politics vary noticeably by city within Napa County. The south side is the most Democratic-leaning (D+35) and the northeast side is the least Democratic-leaning (Even), a spread of about 33 points.
Why Napa 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 Napa County, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 75% of residents in Napa County live in densely developed areas, about 38 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and Napa County sits in the top quarter (about 39%, above 91% of counties).
Walkability and Democratic lean
Places with a highly walkable street grid tend to lean Democratic; Napa County, CA sits in the top quarter nationally on this measure. A walkable street grid does not change how people vote; it mostly reflects how urban a place is.
Why turnout in Napa County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Napa County is in the top quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 66%, about 6 points above the U.S. average of 60%. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Solano County, CA D+21
- Sonoma County, CA D+42
- Marin County, CA D+48
- Contra Costa County, CA D+36
- Yolo County, CA D+35
- San Francisco County, CA D+61
- Alameda County, CA D+49
- Lake County, CA R+4
- San Mateo County, CA D+48
- Sacramento County, CA D+20
Counties with Similar Populations
- Marathon County, WI R+17
- Hampton City, VA D+41
- Florence County, SC Even
- Washington County, WI R+28
- Brunswick County, NC R+29
- Humboldt County, CA D+27
- Monroe County, IN D+29
- Spotsylvania County, VA R+8
- Clark County, OH R+21
- Boone County, KY R+28
All Local Stats
Home Services
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.