Gallatin County leans slightly Democratic by roughly 6 points: about 53% of voters vote Democratic and 47% Republican.
About 84% of adults in Gallatin County typically vote, above the U.S. average of about 62%. Among adults in Gallatin County, ~44% vote Democratic, ~39% Republican, and ~17% don't vote. The map below shows estimated turnout by block group.
How Gallatin County compares
Among counties within 50 miles, Gallatin County is the most Democratic-leaning.
Gallatin County runs about 26 points more Democratic than Montana as a whole. Montana leans Republican overall, while Gallatin County is one of the few Democratic-leaning pockets.
Politics vary noticeably by city within Gallatin County. The southeast side runs the most Democratic (D+29) and the west side runs the most Republican (R+38), a spread of about 67 points.
Why Gallatin 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 Gallatin County, not a ranked or complete list of what matters most.
Areas with high college attainment vote Democratic. About 55% of adults in Gallatin County hold a bachelor's degree, about 26 points above the U.S. average of 28%. Dense areas vote Democratic, and Gallatin County sits in the top fifth on density (about 61%, above 86% of counties). A high never-married share predicts Democratic voting, and about 38% of adults in Gallatin County have never been married, above 90% of counties.
Population density and Democratic lean
Places with high population density tend to lean Democratic; Gallatin County, MT sits in the top quarter nationally on this measure.
Why turnout in Gallatin County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Gallatin County is in the top quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 67%, about 7 points above the U.S. average of 60%. High high-school completion lines up with higher turnout, and about 97% of adults in Gallatin County have completed high school, in the top fraction of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Park County, MT R+14
- Madison County, MT R+46
- Broadwater County, MT R+54
- Sweet Grass County, MT R+54
- Meagher County, MT R+58
- Jefferson County, MT R+38
- Silver Bow County, MT Even
- Lewis and Clark County, MT R+7
- Wheatland County, MT R+66
- Beaverhead County, MT R+42
Counties with Similar Populations
- Douglas County, KS D+35
- Carroll County, GA R+35
- Fayette County, GA R+4
- Potter County, TX R+19
- Lowndes County, GA Even
- Sheboygan County, WI R+15
- Missoula County, MT D+16
- Tom Green County, TX R+39
- Oswego County, NY R+23
- Allegan County, MI R+28
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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.