Jefferson City leans heavily Republican by roughly 38 points: about 31% of voters vote Democratic and 69% Republican.
About 65% of adults in Jefferson City typically vote, near the U.S. average of about 62%. Among adults in Jefferson City, ~20% vote Democratic, ~45% Republican, and ~35% don't vote. The map below shows estimated turnout by block group.
How Jefferson City compares
Among cities within 25 miles, Jefferson City leans more Republican than 10 of 17 neighbors.
Jefferson City runs about 18 points more Republican than Montana as a whole.
Why Jefferson City 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 Jefferson City, not a ranked or complete list of what matters most.
Rural areas vote Republican. About 2% of residents in Jefferson City live in densely developed areas, about 11 points below the Montana average of 13%.
Population density and Republican lean
Places with low population density tend to lean Republican; Jefferson City, MT sits in the bottom tenth nationally on this measure.
Why turnout in Jefferson City looks the way it does
Areas with high high-school completion turn out at higher rates. About 97% of adults in Jefferson City have completed high school, about 7 points above the U.S. average of 90%. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Clancy, MT R+26
- Montana City, MT R+28
- Rimini, MT R+16
- Boulder, MT R+38
- Basin, MT R+38
- Helena, MT D+17
- Helena West Side, MT D+14
- Helena Valley Southeast, MT R+35
- East Helena, MT R+31
Cities with Similar Populations
- Penobscot, ME D+7
- Petronila, TX R+31
- Lenah, VA D+10
- Hamburg, WI R+45
- Flinton, PA R+60
- Usrytown, MS R+48
- Winchester, KS R+54
- Southwest, IN R+64
- Deansboro, NY R+25
- Kempton, IN R+59
Sources and methodology
Precinct-level voting records used to fit the model come from Montana 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.