Clark County is a Republican stronghold. About 18% of voters here vote Democratic and 82% Republican.
About 46% of adults in Clark County typically vote, below the U.S. average of about 62%. Among adults in Clark County, ~8% vote Democratic, ~38% Republican, and ~54% don't vote. The map below shows estimated turnout by block group.
How Clark County compares
Among counties within 50 miles, Clark County leans more Republican than 1 of 3 neighbors.
Clark County runs about 28 points more Republican than Idaho as a whole.
Why Clark 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 Clark County, not a ranked or complete list of what matters most.
Rural areas vote Republican. About 1% of residents in Clark County live in densely developed areas, about 17 points below the Idaho average of 18%.
Developed land and Republican lean
Places with a rural land-use pattern tend to lean Republican; Clark County, ID sits in the bottom tenth nationally on this measure. Developed land does not change how people vote; it mostly reflects how urban a place is.
Why turnout in Clark County looks the way it does
Areas with limited routine healthcare access turn out at lower rates. Clark County is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. Renters vote less often than owners, and about 39% of households in Clark County rent, above 92% of counties. Low high-school completion lines up with lower turnout, and about 74% of adults in Clark County have completed high school, below 98% of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Fremont County, ID R+66
- Madison County, ID R+35
- Jefferson County, ID R+71
- Bonneville County, ID R+43
- Butte County, ID R+75
- Teton County, ID R+21
- Bingham County, ID R+54
- Beaverhead County, MT R+42
- Madison County, MT R+46
- Teton County, WY D+16
Counties with Similar Populations
- Hinsdale County, CO R+6
- Wheeler County, NE R+72
- Keya Paha County, NE R+82
- Treasure County, MT R+66
- Terrell County, TX R+65
- Golden Valley County, MT R+69
- Roberts County, TX R+90
- Kent County, TX R+79
- Bristol Bay Borough, AK Even
- Esmeralda County, NV R+61
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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.