As you probably noted on the ACA Link they parenthetically called the Great River Trail in MS the "Mississippi" Bike Trail. ... however, in times that I have planned &/or did trips in the south MS vicinity I did not remember the ACA dropping south to New Orleans... Meanwhile, I would not be surprised if the official/original Mississippi Bike Path did not and still does go all the way to N.O. but the ACA just did not include it.