Jefferson County is a Republican stronghold. About 23% of voters here vote Democratic and 77% Republican.
About 72% of adults in Jefferson County typically vote, above the U.S. average of about 62%. Among adults in Jefferson County, ~17% vote Democratic, ~55% Republican, and ~28% don't vote. The map below shows estimated turnout by block group.
How Jefferson County compares
Among counties within 50 miles, Jefferson County is the most Republican-leaning.
Jefferson County runs about 53 points more Republican than Pennsylvania as a whole.
Politics vary noticeably by city within Jefferson County. The southwest side is the most Republican-leaning (R+73) and the south side is the least Republican-leaning (R+49), a spread of about 24 points.
Why Jefferson 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 Jefferson County, not a ranked or complete list of what matters most.
Areas with a high white share and below-average college attainment vote Republican. In Jefferson County, about 96% of residents are non-Hispanic white, about 23 points above the U.S. average of 72%; about 18% of adults hold a bachelor's degree, about 7 points below the Pennsylvania average of 26%.
Foreign-born share and voter turnout
Places with a low foreign-born share tend to turn out in mixed patterns; Jefferson County, PA sits in the bottom tenth nationally on this measure.
Why turnout in Jefferson County looks the way it does
Turnout in Jefferson County 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 Counties
- Clearfield County, PA R+46
- Clarion County, PA R+50
- Elk County, PA R+42
- Forest County, PA R+24
- Indiana County, PA R+34
- Armstrong County, PA R+52
- Venango County, PA R+42
- Cameron County, PA R+47
- Cambria County, PA R+35
- Blair County, PA R+37
Counties with Similar Populations
- Barren County, KY R+50
- Stokes County, NC R+57
- McDowell County, NC R+50
- Stephenson County, IL R+14
- Phelps County, MO R+33
- Kittitas County, WA R+8
- Beaufort County, NC R+24
- Delaware County, NY R+17
- Douglas County, WI Even
- Callaway County, MO R+43
Sources and methodology
Precinct-level voting records used to fit the model come from Pennsylvania Department of State, Bureau 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.