Jerome County leans heavily Republican by roughly 48 points: about 26% of voters vote Democratic and 74% Republican.
About 62% of adults in Jerome County typically vote, near the U.S. average of about 62%. Among adults in Jerome County, ~16% vote Democratic, ~46% Republican, and ~38% don't vote. The map below shows estimated turnout by block group.
How Jerome County compares
Among counties within 50 miles, Jerome County leans more Republican than 1 of 6 neighbors.
Jerome County runs about 12 points more Republican than Idaho as a whole.
Politics vary noticeably by city within Jerome County. The southeast side is the most Republican-leaning (R+69) and the northwest side is the least Republican-leaning (R+41), a spread of about 27 points.
Why Jerome 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 Jerome County, not a ranked or complete list of what matters most.
Areas with low college attainment vote Republican. About 14% of adults in Jerome County hold a bachelor's degree, about 13 points below the Idaho average of 26%. A high family-household share predicts Republican voting, and about 78% of households in Jerome County are family households, above 98% of counties.
High-school completion, developed land, and voter turnout
Places that combine low high-school-completion share and a heavily developed built environment tend to turn out at a lower rate, as Jerome County, ID does.
Why turnout in Jerome County looks the way it does
Areas with limited routine healthcare access turn out at lower rates. Jerome County is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The uninsured rate here is about 21%, about 10 points above the Idaho average of 11%. High food insecurity lines up with lower turnout, and about 23% of adults in Jerome County report food insecurity, above 85% of counties. Low high-school completion lines up with lower turnout, and about 73% of adults in Jerome County have completed high school, in the bottom fraction of counties. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Twin Falls County, ID R+45
- Gooding County, ID R+54
- Lincoln County, ID R+63
- Minidoka County, ID R+58
- Cassia County, ID R+63
- Camas County, ID R+72
- Blaine County, ID D+21
- Elmore County, ID R+42
- Power County, ID R+46
- Butte County, ID R+75
Counties with Similar Populations
- Blaine County, ID D+21
- Lincoln County, KY R+64
- Abbeville County, SC R+39
- Fairfax City, VA D+25
- George County, MS R+78
- Dawson County, NE R+35
- Bell County, KY R+62
- Scott County, IN R+53
- Fayette County, TX R+55
- Marion County, MS R+33
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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.