Eastern Giant swallowtail butterfly

Don't forget to update the genus and species information and, more importantly, check out other PN photos of the same to be sure that they are exactly alike. Sometimes there can be some slight differences between male and females of the same species. I can't emphasize enough how important it is to get it right. Other people might depend on the info you provide to make determinations about their spottings. PN is about to eclipse many wildlife pages that document nature so it is paramount to have every spotting correct. If you aren't sure it is best to leave it as unknown. I have hundreds of unknown spottings!

I think your right

This looks like a Giant Swallowtail Butterfly - Papilio cresphontes. Check it out