I just found out that
2,300+ acres were added to Congaree National Park (near Columbia, SC) last November. I'm glad to hear it; it is a beautiful place, one I enjoy visiting any time of the year.
I couldn't find a map of the new boundaries, but according to that article, some of it now borders
Bates Old River, an oxbow to the east of the park.
A few more links time I've spent in the park:
I hope to get back down there soon!