98109 is a Democratic stronghold. About 83% of voters here vote Democratic and 17% Republican.
About 61% of adults in 98109 typically vote, near the U.S. average of about 62%. Among adults in 98109, ~51% vote Democratic, ~10% Republican, and ~39% don't vote. The map below shows estimated turnout by block group.
How 98109 compares
Among zip codes within 15 miles, 98109 leans more Democratic than 53 of 68 neighbors.
98109 runs about 47 points more Democratic than Washington as a whole.
Politics vary noticeably by block within 98109. The northwest side is the most Democratic-leaning (D+76) and the south side is the least Democratic-leaning (D+54), a spread of about 22 points.
Why 98109 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 98109, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 99% of residents in 98109 live in densely developed areas, about 62 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and 98109 sits in the top quarter (about 79%, in the top fraction of zip codes). A high never-married share predicts Democratic voting, and about 59% of adults in 98109 have never been married, above 98% of zip codes.
Paved land cover and Democratic lean
Places with extensive paved surfaces tend to lean Democratic; 98109, WA sits in the top tenth nationally on this measure. Paved ground does not change how people vote; it mostly reflects how urban and built-up a place is.
Why turnout in 98109 looks the way it does
Renters vote less often than owners. About 75% of households in 98109 rent, about 50 points above the U.S. average of 25%. Strong routine healthcare access lines up with higher turnout, and 98109 sits in the top quarter on routine-care measures. 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.