Ilium, New York is a fictional town used as a setting for many of Kurt Vonnegut's novels and short stories. The town's name is likely a clever reference to the Ancient Romans' name for Troy, and the modern day city of the same name.
Ilium is located in the eastern part of the state and is heavily modeled after Schenectady, New York (though Vonnegut makes it clear that the two are different places), where Vonnegut lived and worked as a General Electric public relations writer for several years. Fictitious landmarks of note are the Iroquois River and the Ilium Works, which have their real-world counterparts in the Mohawk River and the Schenectady General Electric plant, respectively.