66603 leans Democratic by roughly 30 points: about 65% of voters vote Democratic and 35% Republican.
About 34% of adults in 66603 typically vote, below the U.S. average of about 62%. Among adults in 66603, ~22% vote Democratic, ~12% Republican, and ~66% don't vote. The map below shows estimated turnout by block group.
How 66603 compares
Among zip codes within 15 miles, 66603 leans more Democratic than 24 of 26 neighbors.
66603 runs about 45 points more Democratic than Kansas as a whole. Kansas leans Republican overall, while 66603 is one of the few Democratic-leaning pockets.
Politics vary noticeably by block within 66603. The southwest side is the most Democratic-leaning (D+36) and the northwest side is the least Democratic-leaning (D+17), a spread of about 19 points.
Why 66603 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 66603, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 97% of residents in 66603 live in densely developed areas, about 60 points above the U.S. average of 36%. A high never-married share predicts Democratic voting, and about 50% of adults in 66603 have never been married, above 95% of zip codes. 66603 runs against the grain of Kansas, a Democratic-leaning pocket in a Republican-leaning state.
Preventive-care access and voter turnout
Places with limited routine preventive-care access tend to turn out at a lower rate; 66603, KS sits in the bottom quarter nationally on this measure. Dental visits do not drive turnout; the rate reflects income, insurance, and healthcare access, which line up with who votes.
Why turnout in 66603 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 66603 is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. The dental-visit rate here is about 49%, about 14 points below the Kansas average of 63%. Renters vote less often than owners, and about 61% of households in 66603 rent, about 36 points above the U.S. average of 25%. High food insecurity lines up with lower turnout, and about 30% of adults in 66603 report food insecurity, above 94% 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 Kansas 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.