Johnston, IA Political Map | Democrat & Republican Areas in Johnston

By the BestNeighborhood data science team. Last updated May 2026.

Johnston leans slightly Democratic by roughly 8 points: about 54% of voters vote Democratic and 46% Republican.

 

About 91% of adults in Johnston typically vote, above the U.S. average of about 62%. Among adults in Johnston, ~49% vote Democratic, ~42% Republican, and ~9% don't vote. The map below shows estimated turnout by block group.

How Johnston compares

Among cities within 25 miles, Johnston leans more Democratic than 64 of 68 neighbors.

Johnston runs about 21 points more Democratic than Iowa as a whole. Iowa leans Republican overall, while Johnston is one of the few Democratic-leaning pockets.

Politics vary noticeably by neighborhood within Johnston. The southwest side runs the most Democratic (D+15) and the northwest side runs the most Republican (R+14), a spread of about 29 points.

Why Johnston 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 Johnston, not a ranked or complete list of what matters most.

Dense areas vote Democratic. About 75% of residents in Johnston live in densely developed areas, about 38 points above the U.S. average of 36%. High college attainment predicts Democratic voting, and Johnston sits in the top quarter (about 58%, above 96% of cities). Johnston runs against the grain of Iowa, a Democratic-leaning pocket in a Republican-leaning state.

Preventive-care access and voter turnout

Places with strong routine preventive-care access tend to turn out at a higher rate; Johnston, IA sits in the top tenth 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 Johnston looks the way it does

Areas with strong routine healthcare access turn out at higher rates. Johnston 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 74%, about 14 points above the U.S. average of 60%. High high-school completion lines up with higher turnout, and about 97% of adults in Johnston have completed high school, above 89% of cities. Learn more about the findings and methodology on the political spectrum map.

Sources and methodology

Precinct-level voting records used to fit the model come from Iowa 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.