P. appalachiensis is thought to have evolved as a hybrid species of two other Papilio butterflies: P. canadensis and P. glaucus. Originally, researchers believed that P. canadensis and P. glaucus were distributed in distinct regions separated by a hybrid zone stretching east from Minnesota to southern New England and south along the Appalachian Mountains. In 2005, researchers suggested these two species interacted at some point and produced the new hybrid P. appalachiensis in the hybrid zone.