App. Tiger Swallowtail 1

This is most likely an Appalachian Tiger Swallowtail (Papilio appalachiensis), although it could very well be an Eastern Tiger Swallowtail (Papilio glaucus) or, perhaps more unlikely, a Canadian Tiger Swallowtail (Papilio canadensis); three very difficult to distinguish species whose ranges overlap to some degree, and in fact until recently they were all considered the same species.