83815 leans heavily Republican by roughly 38 points: about 31% of voters vote Democratic and 69% Republican.
About 79% of adults in 83815 typically vote, above the U.S. average of about 62%. Among adults in 83815, ~25% vote Democratic, ~54% Republican, and ~21% don't vote. The map below shows estimated turnout by block group.
How 83815 compares
Among zip codes within 15 miles, 83815 leans more Republican than 4 of 8 neighbors.
Politically, 83815 sits close to the rest of Idaho.
Politics vary noticeably by block within 83815. The northwest side is the most Republican-leaning (R+51) and the south side is the least Republican-leaning (R+23), a spread of about 28 points.
Why 83815 leans the way it does
This analysis examined 14,881 data points per zip code to find what predicts political lean and turnout. The items below are a few correlations that stood out for 83815, not a ranked or complete list of what matters most.
83815 votes Republican even though it is densely developed (about 85%, far above the Idaho average of 18%). State and regional patterns outweigh the Democratic lean that density usually predicts here.
Paved land cover and Democratic lean
Places with extensive paved surfaces tend to lean Democratic; 83815, ID sits in the top quarter nationally on this measure. Paved ground does not change how people vote; it mostly reflects how urban and built-up a place is.
Why turnout in 83815 looks the way it does
Areas with high high-school completion turn out at higher rates. About 97% of adults in 83815 have completed high school, about 5 points above the Idaho average of 91%. Learn more about the findings and methodology on the political spectrum map.
Nearby Zip Codes
Zip Codes with Similar Populations
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.