Petrolia is a true toss-up. About 52% of voters here vote Democratic and 48% Republican.
About 54% of adults in Petrolia typically vote, below the U.S. average of about 62%. Among adults in Petrolia, ~28% vote Democratic, ~26% Republican, and ~46% don't vote. The map below shows estimated turnout by block group.
How Petrolia compares
Among cities within 25 miles, Petrolia leans more Democratic than 12 of 21 neighbors.
Petrolia runs about 16 points more Republican than California as a whole.
Why Petrolia leans the way it does
Density, race composition, education, and family structure all sit close to their national averages in Petrolia. The lean here lands roughly where demographic data alone would predict.
Population density and Republican lean
Places with low population density tend to lean Republican; Petrolia, CA sits in the bottom tenth nationally on this measure.
Why turnout in Petrolia looks the way it does
Turnout in Petrolia sits close to the national pattern. Routine healthcare access, homeownership, education, and food security all land near their national averages here. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Honeydew, CA D+10
- Scotia, CA R+16
- Rio Dell, CA R+10
- Stafford, CA R+17
- Shively, CA R+16
- Ettersburg, CA D+13
- Redcrest, CA R+14
- Ferndale, CA D+6
- Weott, CA D+21
- Hydesville, CA R+21
Cities with Similar Populations
- Theressa, FL R+65
- Briarcliffe Acres, SC R+27
- Edgar, NE R+68
- Elmwood Park, WI D+13
- Princeton, PA R+51
- Suwannee Valley, FL R+52
- Irwin, OH R+58
- Nogalus, TX R+78
- Speed, WV R+60
- Richardson, IL R+33
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.