83858 is a Republican stronghold. About 20% of voters here vote Democratic and 80% Republican.
About 79% of adults in 83858 typically vote, above the U.S. average of about 62%. Among adults in 83858, ~16% vote Democratic, ~63% Republican, and ~21% don't vote. The map below shows estimated turnout by block group.
How 83858 compares
Among zip codes within 15 miles, 83858 leans more Republican than 7 of 9 neighbors.
83858 runs about 23 points more Republican than Idaho as a whole.
Politics vary noticeably by block within 83858. The northwest side is the most Republican-leaning (R+66) and the south side is the least Republican-leaning (R+56), a spread of about 10 points.
Why 83858 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 83858, not a ranked or complete list of what matters most.
Areas with many family households vote Republican. About 81% of households in 83858 are family households, about 15 points above the U.S. average of 67%.
Population density and Democratic lean
Places with high population density tend to lean Democratic; 83858, ID sits above the national average on this measure.
Why turnout in 83858 looks the way it does
Turnout in 83858 sits close to the national pattern. Routine healthcare access, homeownership, education, and food security all land near their national averages here. 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.