Black Diamond leans slightly Democratic by roughly 12 points: about 56% of voters vote Democratic and 44% Republican.
About 82% of adults in Black Diamond typically vote, above the U.S. average of about 62%. Among adults in Black Diamond, ~46% vote Democratic, ~36% Republican, and ~18% don't vote. The map below shows estimated turnout by block group.
How Black Diamond compares
Among cities within 25 miles, Black Diamond leans more Democratic than 38 of 83 neighbors.
Black Diamond runs about 6 points more Republican than Washington as a whole.
Politics vary noticeably by neighborhood within Black Diamond. The northeast side is the most Democratic-leaning (D+20) and the west side is the least Democratic-leaning (D+5), a spread of about 14 points.
Why Black Diamond leans the way it does
This analysis examined 14,881 data points per city to find what predicts political lean and turnout. The items below are a few correlations that stood out for Black Diamond, not a ranked or complete list of what matters most.
Areas with high college attainment vote Democratic. About 51% of adults in Black Diamond hold a bachelor's degree, about 23 points above the U.S. average of 28%. Dense areas vote Democratic, and Black Diamond sits in the top fifth on density (about 29%, above 80% of cities).
Population density and Democratic lean
Places with high population density tend to lean Democratic; Black Diamond, WA sits in the top quarter nationally on this measure.
Why turnout in Black Diamond looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Black Diamond 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 75%, about 15 points above the U.S. average of 60%. High high-school completion lines up with higher turnout, and about 97% of adults in Black Diamond have completed high school, above 88% of cities. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Kummer, WA D+8
- Maple Valley, WA D+17
- Lake Morton-Berrydale, WA D+6
- Ravensdale, WA R+8
- Kanaskat, WA R+7
- Wabash, WA R+31
- Covington, WA D+11
- Cumberland, WA R+22
- Hobart, WA D+4
- Kangley, WA R+19
Cities with Similar Populations
- Cave Junction, OR R+22
- Myersville, MD R+15
- Rye, NH D+18
- Tuskegee Institute, AL D+84
- Kent City, MI R+40
- Vandercook Lake, MI R+18
- Elkton, KY R+66
- West Bradenton, FL R+23
- Lochridge, TX R+31
- Holly Hill, SC D+33
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.