1. Elkton Hills: This was a prep school in Pennsylvania where Holden was expelled for failing his classes, specifically history and Latin.
2. Pency Prep: This was a boarding school in Pennsylvania where Holden was expelled for failing his classes, specifically history and English. It's the school he's narrating from in the book.
3. "Another one in New York" (unnamed): Holden doesn't name this school, but he mentions he got kicked out for "being a psycho" after he got into a fight with a guy named Stradlater. This incident is never explicitly described, but it is implied to be a fight over a girl.
It's worth noting that Holden's expulsion from these schools is just one reflection of his overall discontent with the "phony" world of adults and the rigid, meaningless structures of traditional education. He struggles to find his place in the world and constantly rebels against authority.