I know, but it just doesn't seem like a significant enough part of the US to be the origin of the name. It feels like Mexico naming itself Rio Grande upon independence.Well, I meant more after the actual Appalachian Mountains, but just call it Appalachia for short.
https://en.wikipedia.org/wiki/Appalachian_Mountains
However, if the Revolution ends the same way it did IOTL the Appalachian Mountains would be in the middle of the nation so perhaps that could be used as a justification for a name change (maybe the name of the US is changed as a part of the new constitution that replaces the Articles?).