Umatilla County leans heavily Republican by roughly 34 points: about 33% of voters vote Democratic and 67% Republican.
About 64% of adults in Umatilla County typically vote, near the U.S. average of about 62%. Among adults in Umatilla County, ~21% vote Democratic, ~43% Republican, and ~36% don't vote. The map below shows estimated turnout by block group.
How Umatilla County compares
Among counties within 50 miles, Umatilla County leans more Republican than 3 of 4 neighbors.
Umatilla County runs about 48 points more Republican than Oregon as a whole. Oregon leans Democratic overall, while Umatilla County is one of the few Republican-leaning pockets.
Politics vary noticeably by city within Umatilla County. The southwest side is the most Republican-leaning (R+56) and the southeast side is the least Republican-leaning (R+12), a spread of about 44 points.
Why Umatilla 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 Umatilla County, not a ranked or complete list of what matters most.
Umatilla County votes Republican even though it is densely developed (about 47%, well above the Oregon average of 31%). State and regional patterns outweigh the Democratic lean that density usually predicts here. A high family-household share predicts Republican voting, and about 72% of households in Umatilla County are family households, above 87% of counties. Umatilla County runs against the grain of Oregon, a Republican-leaning pocket in a Democratic-leaning state.
Non-English at home and voter turnout
Places with a low non-English-at-home share tend to turn out at a higher rate; Umatilla County, OR sits in the bottom tenth nationally on this measure.
Why turnout in Umatilla County looks the way it does
Areas with limited routine healthcare access turn out at lower rates. Umatilla County is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. Learn more about the findings and methodology on the political spectrum map.
Nearby Counties
- Morrow County, OR R+36
- Benton County, WA R+21
- Walla Walla County, WA R+7
- Franklin County, WA R+16
- Union County, OR R+33
- Columbia County, WA R+51
- Gilliam County, OR R+48
- Adams County, WA R+31
- Garfield County, WA R+58
- Wallowa County, OR R+20
Counties with Similar Populations
- Natrona County, WY R+41
- Kosciusko County, IN R+47
- Putnam County, TN R+43
- Clinton County, NY R+5
- Hancock County, IN R+36
- Floyd County, IN R+18
- Clearfield County, PA R+46
- Caldwell County, NC R+47
- Bedford County, VA R+43
- Wagoner County, OK R+40
Sources and methodology
Precinct-level voting records used to fit the model come from Oregon Secretary of State, Elections Division, 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.