99021 leans Republican by roughly 28 points: about 36% of voters vote Democratic and 64% Republican.
About 90% of adults in 99021 typically vote, above the U.S. average of about 62%. Among adults in 99021, ~32% vote Democratic, ~58% Republican, and ~10% don't vote. The map below shows estimated turnout by block group.
How 99021 compares
Among zip codes within 15 miles, 99021 leans more Republican than 20 of 26 neighbors.
99021 runs about 46 points more Republican than Washington as a whole. Washington leans Democratic overall, while 99021 is one of the few Republican-leaning pockets.
Politics vary noticeably by block within 99021. The east side is the most Republican-leaning (R+33) and the west side is the least Republican-leaning (R+23), a spread of about 10 points.
Why 99021 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 99021, not a ranked or complete list of what matters most.
99021 votes against the grain of Washington. Washington leans Democratic overall, while 99021 runs about 46 points more Republican. A high family-household share predicts Republican voting, and about 78% of households in 99021 are family households, above 87% of zip codes.
Cancer-screening access and voter turnout
Places with high colon-cancer-screening access tend to turn out at a higher rate; 99021, WA sits in the top quarter nationally on this measure. Cancer screening does not drive turnout; it reflects income, insurance, and healthcare access.
Why turnout in 99021 looks the way it does
Areas with strong routine healthcare access turn out at higher rates. 99021 is in the top quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 69%, about 9 points above the U.S. average of 60%. Homeowners vote more often than renters, and about 92% of households in 99021 own their home, compared to around 62% 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.