If America got dismantled for some reason, I would think that it would be split into different states and territories.
New England would obviously just be the New England states.
The southern states that broke apart from the Union in the 1860's would form a territory which would probably include Kentucky, Maryland and possibly Oklahoma.
The midwestern states would probably be the largest by square miles, forming from Ohio to Kansas and possibly western Montana.
The West would be split between the states that touch the Pacific, and those crammed between the Rockies and Sierra Nevada/Cascades mountain ranges.
And I would imagine that New Jersey would be like North Korea of America, just so we can keep the Jersey Shore cast in there and not leave.