Summerville leans Republican by roughly 18 points: about 41% of voters vote Democratic and 59% Republican.
About 73% of adults in Summerville typically vote, above the U.S. average of about 62%. Among adults in Summerville, ~30% vote Democratic, ~43% Republican, and ~27% don't vote. The map below shows estimated turnout by block group.
How Summerville compares
Among cities within 25 miles, Summerville leans more Republican than 29 of 51 neighbors.
Politically, Summerville sits close to the rest of South Carolina.
Politics vary noticeably by neighborhood within Summerville. The east side runs the most Democratic (D+4) and the west side runs the most Republican (R+25), a spread of about 29 points.
Why Summerville 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 Summerville, not a ranked or complete list of what matters most.
Summerville votes Republican even though it is densely developed (about 66%, far above the South Carolina average of 24%). State and regional patterns outweigh the Democratic lean that density usually predicts here.
Paved land cover and Democratic lean
Places with extensive paved surfaces tend to lean Democratic; Summerville, SC 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 Summerville looks the way it does
Turnout in Summerville sits close to the national pattern. Routine healthcare access, homeownership, education, and food security all land near their national averages here. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Lincolnville, SC D+19
- Ladson, SC D+3
- Dorchester Estates, SC R+26
- Slandsville, SC R+29
- Jedburg, SC R+20
- Givhans, SC R+34
- Goose Creek, SC R+5
- Long Ridge, SC R+19
- Ridgeville, SC R+20
- Strawberry, SC R+22
Cities with Similar Populations
- Metairie, LA R+14
- Everett, WA D+17
- Pasadena, CA D+51
- Lafayette, LA R+11
- Pearland, TX Even
- Mission, TX R+4
- Cedar Rapids, IA D+15
- Orange, CA D+6
- South Bend, IN D+22
- Broken Arrow, OK R+16
All Local Stats
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Sources and methodology
Precinct-level voting records used to fit the model come from South Carolina State Election Commission, 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.