Sullivans Island leans slightly Republican by roughly 12 points: about 44% of voters vote Democratic and 56% Republican.
About 89% of adults in Sullivans Island typically vote, above the U.S. average of about 62%. Among adults in Sullivans Island, ~39% vote Democratic, ~50% Republican, and ~11% don't vote. The map below shows estimated turnout by block group.
How Sullivans Island compares
Among cities within 25 miles, Sullivans Island leans more Republican than 23 of 26 neighbors.
Sullivans Island runs about 7 points more Democratic than South Carolina as a whole.
Why Sullivans Island 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 Sullivans Island, not a ranked or complete list of what matters most.
Sullivans Island votes Republican even though it is densely developed (about 20%, about 17 points below the U.S. average of 36%). State and regional patterns outweigh the Democratic lean that density usually predicts here.
Food insecurity and voter turnout
Places with low food insecurity tend to turn out at a higher rate; Sullivans Island, SC sits in the bottom tenth nationally on this measure. Food insecurity does not directly drive turnout; it reflects economic hardship, which lines up with lower voting.
Why turnout in Sullivans Island looks the way it does
Areas with strong routine healthcare access turn out at higher rates. Sullivans Island 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 79%, about 19 points above the U.S. average of 60%. High high-school completion lines up with higher turnout, and more than 99% of adults in Sullivans Island have completed high school, in the top fraction of cities. Learn more about the findings and methodology on the political spectrum map.
Nearby Cities
- Isle Of Palms, SC R+14
- Mount Pleasant, SC R+10
- Charleston, SC Even
- Folly Beach, SC R+3
- Wando, SC R+2
- Awendaw, SC R+10
- Johns Island, SC R+6
- Hanahan, SC R+19
- North Charleston, SC D+37
- Charleston Afb, SC D+11
Cities with Similar Populations
- Wellington, AL R+82
- Newport, ME R+26
- Annville, KY R+72
- Creola, AL R+50
- Neoga, IL R+57
- Tower City, PA R+57
- Turbotville, PA R+52
- Lesage, WV R+51
- Duquesne, MO R+39
- Belle Plaine, IA R+30
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.