Is shisha tobacco.....?

I don't understand why here in Chicago hookah bars serve flavored tobacco, but back home in Portland, Oregon the hookah bars served "shisha" to anyone and did not ask for id. There was a separate lounge for the tobacco and I never saw anyone go in there. I was also underage when I last went to one, so this concerns me a little. Just wondering... unless shisha is NOT tobacco, though everyone here is insisting it IS. Anyway, everyone I know wants to know for sure.