This reference to Seaton Sledd comes from a 1788 South Carolina newspaper--he's got a letter at the post office. The notice indicates that unclaimed letters will be returned.
Friday, June 6, 1788
Paper: City Gazette (Charleston, SC)--obtained onGenealogybank.com
It is evidence that someone thought he lived in "Congarees." You don't write letters to yourself.
The reality is that Seaton probably did live where the letter indicates. But it is worth keeping in mind what a record or item says and what it does not say.
Especially if other evidence flies in the face of one piece of information.