Bonneville County leans heavily Republican by roughly 44 points: about 28% of voters vote Democratic and 72% Republican.
About 75% of adults in Bonneville County typically vote, above the U.S. average of about 62%. Among adults in Bonneville County, ~21% vote Democratic, ~54% Republican, and ~25% don't vote. The map below shows estimated turnout by block group.
How Bonneville County compares
Among counties within 50 miles, Bonneville County leans more Republican than 3 of 6 neighbors.
Bonneville County runs about 7 points more Republican than Idaho as a whole.
Politics vary noticeably by city within Bonneville County. The northeast side is the most Republican-leaning (R+60) and the west side is the least Republican-leaning (R+33), a spread of about 27 points.
Why Bonneville 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 Bonneville County, not a ranked or complete list of what matters most.
Bonneville County votes Republican even though it is densely developed (about 70%, far above the Idaho average of 18%). State and regional patterns outweigh the Democratic lean that density usually predicts here. A high family-household share predicts Republican voting, and about 72% of households in Bonneville County are family households, above 87% of counties.
Population density and Democratic lean
Places with high population density tend to lean Democratic; Bonneville County, ID sits in the top tenth nationally on this measure.
Why turnout in Bonneville County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Bonneville 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 68%, about 8 points above the U.S. average of 60%. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Jefferson County, ID R+71
- Madison County, ID R+35
- Bingham County, ID R+54
- Fremont County, ID R+66
- Teton County, ID R+21
- Bannock County, ID R+25
- Clark County, ID R+65
- Teton County, WY D+16
- Caribou County, ID R+73
- Power County, ID R+46
Counties with Similar Populations
- Gregg County, TX R+28
- Kennebec County, ME R+7
- Faulkner County, AR R+30
- Morgan County, AL R+43
- Saline County, AR R+41
- Richland County, OH R+27
- Blair County, PA R+37
- Jasper County, MO R+40
- Cochise County, AZ R+20
- Berkeley County, WV R+33
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.