I immediately think of Ft. Jackson near Savannah, Georgia. Also, there WERE several around Charleston, But I can't think of any still preserved. If one goes to 96 and sees the Star fort there, some of the redoubts from the siege are visible, even though it was a, relatively, small battle/siege and all early earthen stuff.
The Fort was, mainly, a British fortification during the American War and was the innermost "regular" fort used by the British forces. The VAST majority, if not all (some debate), of the British forces there were Loyalist colonials, from South Carolina, New York, and New Jersey.
It was assaulted by Greene and a decent chunk of the southern portion of the American regular forces. (VERY interesting site! Now not really near much, but only 20 miles or so from me.)