Adams County is a Republican stronghold. About 22% of voters here vote Democratic and 78% Republican.
About 81% of adults in Adams County typically vote, above the U.S. average of about 62%. Among adults in Adams County, ~18% vote Democratic, ~64% Republican, and ~18% don't vote. The map below shows estimated turnout by block group.
How Adams County compares
Adams County sits in a sparsely populated area with few comparable counties nearby.
Adams County runs about 21 points more Republican than Idaho as a whole.
Politics vary noticeably by city within Adams County. The west side is the most Republican-leaning (R+61) and the northeast side is the least Republican-leaning (R+51), a spread of about 11 points.
Why Adams 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 Adams County, not a ranked or complete list of what matters most.
Rural areas vote Republican. About 7% of residents in Adams County live in densely developed areas, about 11 points below the Idaho average of 18%.
Paved land cover and Republican lean
Places with little paved surface tend to lean Republican; Adams County, ID sits in the bottom 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 Adams County looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Adams 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 66%, about 6 points above the U.S. average of 60%. Homeowners vote more often than renters, and about 84% of households in Adams County own their home, above 95% of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Valley County, ID R+41
- Washington County, ID R+57
- Wallowa County, OR R+20
- Payette County, ID R+57
- Gem County, ID R+58
- Boise County, ID R+50
- Baker County, OR R+41
- Malheur County, OR R+42
- Idaho County, ID R+64
- Ada County, ID R+8
Counties with Similar Populations
- Wahkiakum County, WA R+19
- Calhoun County, IL R+56
- Marshall County, SD R+31
- Guadalupe County, NM Even
- Mills County, TX R+72
- Deuel County, SD R+54
- Kimble County, TX R+63
- Custer County, ID R+52
- Dewey County, OK R+78
- Lincoln County, NV R+66
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.