85021 leans Democratic by roughly 24 points: about 62% of voters vote Democratic and 38% Republican.
About 53% of adults in 85021 typically vote, below the U.S. average of about 62%. Among adults in 85021, ~33% vote Democratic, ~20% Republican, and ~47% don't vote. The map below shows estimated turnout by block group.
How 85021 compares
Among zip codes within 15 miles, 85021 leans more Democratic than 41 of 67 neighbors.
85021 runs about 30 points more Democratic than Arizona as a whole. Arizona leans Republican overall, while 85021 is one of the few Democratic-leaning pockets.
Politics vary noticeably by block within 85021. The west side is the most Democratic-leaning (D+38) and the southeast side is the least Democratic-leaning (D+4), a spread of about 34 points.
Why 85021 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 85021, not a ranked or complete list of what matters most.
Dense areas vote Democratic. More than 99% of residents in 85021 live in densely developed areas, about 63 points above the U.S. average of 36%. A high never-married share predicts Democratic voting, and about 43% of adults in 85021 have never been married, above 91% of zip codes. 85021 runs against the grain of Arizona, a Democratic-leaning pocket in a Republican-leaning state.
Paved land cover and Democratic lean
Places with extensive paved surfaces tend to lean Democratic; 85021, AZ 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 85021 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 85021 is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. Renters vote less often than owners, and about 56% of households in 85021 rent, about 31 points above the U.S. average of 25%. High food insecurity lines up with lower turnout, and about 22% of adults in 85021 report food insecurity, above 83% of 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 Arizona 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.