Petrolia is a Republican stronghold. About 19% of voters here vote Democratic and 81% Republican.
About 90% of adults in Petrolia typically vote, above the U.S. average of about 62%. Among adults in Petrolia, ~17% vote Democratic, ~73% Republican, and ~10% don't vote. The map below shows estimated turnout by block group.
How Petrolia compares
Among cities within 25 miles, Petrolia leans more Republican than 28 of 59 neighbors.
Petrolia runs about 73 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Petrolia is one of the few Republican-leaning pockets.
Why Petrolia leans the way it does
This analysis examined 14,881 data points per city to find what predicts political lean and turnout. The items below are a few correlations that stood out for Petrolia, not a ranked or complete list of what matters most.
Car-dependent areas vote Republican. About 95% of residents in Petrolia drive to work alone, about 21 points above the U.S. average of 74%. Petrolia runs against the grain of Illinois, a Republican-leaning pocket in a Democratic-leaning state.
Population density and Republican lean
Places with low population density tend to lean Republican; Petrolia, IL sits in the bottom quarter 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
- Bridgeport, IL R+58
- Sumner, IL R+52
- Birds, IL R+56
- Lawrenceville, IL R+42
- Port Jackson, IL R+65
- Pinkstaff, IL R+60
- Claremont, IL R+32
- Landes, IL R+67
- Flat Rock, IL R+64
- Helena, IL R+70
Cities with Similar Populations
- Adamsburg, SC R+47
- Wheatland, ND R+49
- Sargeant, MN R+47
- Hawkinstown, VA R+47
- Griffith, MS R+6
- Wallace, IN R+63
- Sandy Beach, IN R+51
- Lyons, SD R+54
- Mount Ida, WI R+43
- Waterford, MN R+21
All Local Stats
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Sources and methodology
Precinct-level voting records used to fit the model come from Illinois State Board of 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.