They come from all over the country, as you can see. None of the non-Muslim authorities who so confidently tell us that the Islamic State has nothing to do with Islam have explained why this misunderstanding of Islam is so widespread in the U.S. and elsewhere.
Map from “The Islamic State’s suspected inroads into America,” by Adam Goldman, Jia Lynn Yang and John Muyskens, Washington Post, September 8, 2015 (thanks to The Religion of Peace).