Port Byron leans Republican by roughly 22 points: about 39% of voters vote Democratic and 61% Republican.
About 81% of adults in Port Byron typically vote, above the U.S. average of about 62%. Among adults in Port Byron, ~31% vote Democratic, ~49% Republican, and ~20% don't vote. The map below shows estimated turnout by block group.
How Port Byron compares
Among cities within 25 miles, Port Byron leans more Republican than 20 of 77 neighbors.
Port Byron runs about 33 points more Republican than Illinois as a whole. Illinois leans Democratic overall, while Port Byron is one of the few Republican-leaning pockets.
Why Port Byron 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 Port Byron, not a ranked or complete list of what matters most.
Port Byron votes against the grain of Illinois. Illinois leans Democratic overall, while Port Byron runs about 33 points more Republican.
Walkability and Republican lean
Places with a low walkability score tend to lean Republican; Port Byron, IL sits below the national average on this measure. A walkable street grid does not change how people vote; it mostly reflects how urban a place is.
Why turnout in Port Byron looks the way it does
Areas with high high-school completion turn out at higher rates. About 96% of adults in Port Byron have completed high school, about 6 points above the U.S. average of 90%. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Rapids City, IL R+25
- Le Claire, IA R+18
- Pleasant Valley, IA R+15
- Hampton, IL Even
- Barstow, IL R+22
- Cordova, IL R+30
- Princeton, IA R+31
- Hillsdale, IL R+31
- Cleveland, IL R+27
- Osborn, IL R+24
Cities with Similar Populations
- Beaver, WV R+49
- Ponce Inlet, FL R+27
- Edgewood, TX R+72
- Lockbourne, OH R+32
- Hermann, MO R+50
- Angwin, CA D+26
- Lisbon, IA R+19
- Millington, NJ Even
- Daleville, IN R+44
- Bottineau, ND R+43
Sources and methodology
Precinct-level voting records used to fit the model come from Illinois State Board of 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.