I have researched that location and if you look at it on Good=gle Maps, there is no way to trace where the location was in the swamp.No markers, no sign posts ar land marks,it is fundamentally obscure.
I find Francis Marion fascinating.Some say his ancestray was from Ireland. But it may be French.He is one of the genuine heros of America who is not lauded enough IMHO.
I went to Ancestry and looked him up. He is full French at least for 4 generations. Both his paternal and maternal lines are French. Not an Irish among them!