Jefferson County leans Republican by roughly 26 points: about 37% of voters vote Democratic and 63% Republican.
About 73% of adults in Jefferson County typically vote, above the U.S. average of about 62%. Among adults in Jefferson County, ~27% vote Democratic, ~46% Republican, and ~27% don't vote. The map below shows estimated turnout by block group.
How Jefferson County compares
Jefferson County sits in a sparsely populated area with few comparable counties nearby.
Jefferson County runs about 40 points more Republican than Oregon as a whole. Oregon leans Democratic overall, while Jefferson County is one of the few Republican-leaning pockets.
Politics vary noticeably by city within Jefferson County. The northwest side runs the most Democratic (D+63) and the south side runs the most Republican (R+50), a spread of about 112 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.
Jefferson County votes against the grain of Oregon. Oregon leans Democratic overall, while Jefferson County runs about 40 points more Republican. A high family-household share predicts Republican voting, and about 72% of households in Jefferson County are family households, above 87% of counties.
Non-English at home and voter turnout
Places with a low non-English-at-home share tend to turn out at a higher rate; Jefferson County, OR sits in the bottom quarter 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
- Crook County, OR R+44
- Deschutes County, OR D+5
- Wheeler County, OR R+51
- Wasco County, OR R+14
- Sherman County, OR R+59
- Hood River County, OR D+24
- Gilliam County, OR R+48
- Klickitat County, WA R+11
- Skamania County, WA R+13
- Clackamas County, OR D+13
Counties with Similar Populations
- Randolph County, IN R+55
- Texas County, MO R+67
- Waushara County, WI R+33
- Marion County, MS R+33
- Uvalde County, TX R+23
- Fayette County, TX R+55
- Burke County, GA R+7
- Nicholas County, WV R+60
- Scott County, IN R+53
- Somerset County, MD Even
Sources and methodology
Precinct-level voting records used to fit the model come from Oregon Secretary of State, Elections Division, 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.