Canyon County leans heavily Republican by roughly 40 points: about 30% of voters vote Democratic and 70% Republican.
About 65% of adults in Canyon County typically vote, near the U.S. average of about 62%. Among adults in Canyon County, ~20% vote Democratic, ~45% Republican, and ~35% don't vote. The map below shows estimated turnout by block group.
How Canyon County compares
Among counties within 50 miles, Canyon County leans more Republican than 1 of 7 neighbors.
Politically, Canyon County sits close to the rest of Idaho.
Politics vary noticeably by city within Canyon County. The northeast side is the most Republican-leaning (R+68) and the southeast side is the least Republican-leaning (R+35), a spread of about 33 points.
Why Canyon 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 Canyon County, not a ranked or complete list of what matters most.
Canyon County votes Republican even though it is densely developed (about 71%, 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 73% of households in Canyon County are family households, above 92% of counties.
Population density and Democratic lean
Places with high population density tend to lean Democratic; Canyon County, ID sits in the top tenth nationally on this measure.
Why turnout in Canyon County looks the way it does
Areas with limited routine healthcare access turn out at lower rates. Canyon County is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Ada County, ID R+8
- Owyhee County, ID R+63
- Gem County, ID R+58
- Payette County, ID R+57
- Malheur County, OR R+42
- Boise County, ID R+50
- Washington County, ID R+57
- Elmore County, ID R+42
- Valley County, ID R+41
- Adams County, ID R+57
Counties with Similar Populations
- Baldwin County, AL R+53
- Linn County, IA D+7
- Oneida County, NY R+13
- Berkeley County, SC R+13
- Lake County, OH R+11
- Barnstable County, MA D+20
- Montgomery County, AL D+38
- Smith County, TX R+28
- Mahoning County, OH Even
- Brazos County, TX D+6
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.