We have a few local Indian tribes here in California who "run" their tribal casinos. It's MOSTLY a joke. No, it's kind of sad to see--SO tacky, run down and hardly worth the effort. They are CERTAINLY no threat WHATSOEVER to Vegas. NO ONE is.
I see them going the way of the dodo eventually.
The three biggest Indian casinos are Foxwoods, in Ledyard, CT, Mohegan Sun in Uncasville CT and the Seminole Hard Rock in Tampa, FL.