99138 leans slightly Democratic by roughly 12 points: about 56% of voters vote Democratic and 44% Republican.
About 51% of adults in 99138 typically vote, below the U.S. average of about 62%. Among adults in 99138, ~29% vote Democratic, ~22% Republican, and ~49% don't vote. The map below shows estimated turnout by block group.
How 99138 compares
Among zip codes within 15 miles, 99138 is the most Democratic-leaning.
99138 runs about 6 points more Republican than Washington as a whole.
Why 99138 leans the way it does
This analysis examined 14,881 data points per zip code to find what predicts political lean and turnout. The items below are a few correlations that stood out for 99138, not a ranked or complete list of what matters most.
Areas with many never-married adults vote Democratic. About 38% of adults in 99138 have never been married, well above similar-sized zip codes (around 23%).
Cancer-screening access and voter turnout
Places with low colon-cancer-screening access tend to turn out at a lower rate; 99138, WA sits in the bottom quarter nationally on this measure. Cancer screening does not drive turnout; it reflects income, insurance, and healthcare access.
Why turnout in 99138 looks the way it does
High-crime urban areas turn out at lower rates, mostly because the housing stress common in those areas makes voting harder. 99138 sits in the top 15% nationally on a violent-crime measure. See CrimeGrade for more details. Renters vote less often than owners, and about 39% of households in 99138 rent, compared to around 20% in nearby zip codes. Learn more about the findings and methodology on the political spectrum map.
Nearby Zip Codes
Zip Codes with Similar Populations
Sources and methodology
Precinct-level voting records used to fit the model come from Washington 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.