According to the South Carolina Election Commission, you must drop your ballot off at your county voter registration office by 7PM on election day. Details on the location, email address, website, and phone number for the voter registration office in Dorchester County is as follows:
- Dorchester County Board of Voter Registration and Elections, 201 Johnston Street, St. George, SC 29477 (source)
- https://www.scvotes.gov/dorchester
- Email: vote@dorchestercountysc.gov
- Phone: (843) 563-0132 or (843) 832-0132