99128 is a Republican stronghold. About 24% of voters here vote Democratic and 76% Republican.
About 55% of adults in 99128 typically vote, below the U.S. average of about 62%. Among adults in 99128, ~13% vote Democratic, ~42% Republican, and ~45% don't vote. The map below shows estimated turnout by block group.
How 99128 compares
Among zip codes within 15 miles, 99128 leans more Republican than 3 of 8 neighbors.
99128 runs about 57 points more Republican than Washington as a whole. Washington leans Democratic overall, while 99128 is one of the few Republican-leaning pockets.
Why 99128 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 99128, not a ranked or complete list of what matters most.
99128 votes against the grain of Washington. Washington leans Democratic overall, while 99128 runs about 57 points more Republican. Rural areas vote Republican, and 99128 sits in the bottom quarter on density (about 4%, below 89% of zip codes).
Walkability and Republican lean
Places with a low walkability score tend to lean Republican; 99128, WA sits in the bottom quarter nationally on this measure. A walkable street grid does not change how people vote; it mostly reflects how urban a place is.
Why turnout in 99128 looks the way it does
Areas with strong routine healthcare access turn out at higher rates. 99128 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 72%, about 12 points above the U.S. average of 60%. 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.