Twin Falls County leans heavily Republican by roughly 44 points: about 28% of voters vote Democratic and 72% Republican.
About 68% of adults in Twin Falls County typically vote, above the U.S. average of about 62%. Among adults in Twin Falls County, ~19% vote Democratic, ~49% Republican, and ~32% don't vote. The map below shows estimated turnout by block group.
How Twin Falls County compares
Among counties within 50 miles, Twin Falls County is the least Republican-leaning.
Twin Falls County runs about 8 points more Republican than Idaho as a whole.
Politics vary noticeably by city within Twin Falls County. The southwest side is the most Republican-leaning (R+70) and the east side is the least Republican-leaning (R+41), a spread of about 29 points.
Why Twin Falls 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 Twin Falls County, not a ranked or complete list of what matters most.
Twin Falls County votes Republican even though it is densely developed (about 61%, far above the Idaho average of 18%). State and regional patterns outweigh the Democratic lean that density usually predicts here. A high family-household share predicts Republican voting, and about 71% of households in Twin Falls County are family households, above 82% of counties.
Population density and Democratic lean
Places with high population density tend to lean Democratic; Twin Falls County, ID sits in the top quarter nationally on this measure.
Why turnout in Twin Falls County looks the way it does
Turnout in Twin Falls County 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 Counties
- Jerome County, ID R+48
- Gooding County, ID R+54
- Lincoln County, ID R+63
- Cassia County, ID R+63
- Minidoka County, ID R+58
- 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
- Nassau County, FL R+47
- Dodge County, WI R+30
- Rockingham County, NC R+31
- St. Clair County, AL R+65
- Grafton County, NH D+18
- Christian County, MO R+51
- Wayne County, NY R+23
- Victoria County, TX R+28
- Frederick County, VA R+25
- Lapeer County, MI R+38
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.