Like the other tiger swallowtails, the western tiger swallowtail was formerly classified in genus Pterourus, but modern classifications all agree in placing them within Papilio.
This common species is present in western North America. The normal range of the western tiger swallowtail covers much of western North America, from British Columbia to North Dakota in the north to Baja California and New Mexico in the south. Individuals occasionally turn up east of this range; in eastern North America, though, it is replaced by the similar eastern tiger swallowtail, Papilio glaucus.
These butterflies are frequently seen in urban parks and gardens, as well as in rural woodlands and riparian areas.