The SC Room of the Charleston County Main Library has in its Fort Johnson file a map/article published by the Post and Courier during the Centennial that shows the Charleston defenses and their state as of the date of the article.

There are still some earthworks outside the Peninsula in existence today - the earthworks beside Christ Episcopal Church in Mt. Pleasant come to mind. There are also some in James Island. I have heard, but not verified, that construction around the St. Francis Hospital in West Ashley has brought to light (by allowing easier access) some earthworks still in existence.