Bannock County leans Republican by roughly 24 points: about 38% of voters vote Democratic and 62% Republican.
About 69% of adults in Bannock County typically vote, above the U.S. average of about 62%. Among adults in Bannock County, ~26% vote Democratic, ~43% Republican, and ~31% don't vote. The map below shows estimated turnout by block group.
How Bannock County compares
Among counties within 50 miles, Bannock County is the least Republican-leaning.
Bannock County runs about 12 points more Democratic than Idaho as a whole.
Politics vary noticeably by city within Bannock County. The northeast side runs the most Democratic (D+8) and the southeast side runs the most Republican (R+62), a spread of about 70 points.
Why Bannock 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 Bannock County, not a ranked or complete list of what matters most.
Bannock County votes Republican even though it is densely developed (about 65%, far above the Idaho average of 18%). State and regional patterns outweigh the Democratic lean that density usually predicts here.
Population density and Democratic lean
Places with high population density tend to lean Democratic; Bannock County, ID sits in the top quarter nationally on this measure.
Why turnout in Bannock County looks the way it does
Areas with high high-school completion turn out at higher rates. About 94% of adults in Bannock County have completed high school, above 81% of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Power County, ID R+46
- Bingham County, ID R+54
- Caribou County, ID R+73
- Oneida County, ID R+76
- Bonneville County, ID R+43
- Franklin County, ID R+77
- Jefferson County, ID R+71
- Bear Lake County, ID R+71
- Minidoka County, ID R+58
- Butte County, ID R+75
Counties with Similar Populations
- Island County, WA D+10
- Lincoln County, NC R+45
- Polk County, OR R+4
- Burke County, NC R+40
- Muskingum County, OH R+41
- Angelina County, TX R+41
- Cullman County, AL R+76
- Lawrence County, PA R+28
- Elmore County, AL R+47
- Josephine County, OR R+25
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Sources and methodology
Precinct-level voting records used to fit the model come from Idaho 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.