The Ilidaria system was an inhabited planetary system in the Delta Quadrant. One of its planets, Ilidaria, was the homeworld of the Ilidarians. This system was located less than three light years from a type-4 quantum singularity. (VOY: "Parallax")
This system was only mentioned in dialogue.
According to Star Trek: Star Charts (p. 83), this was a binary system with a pair of F-class stars. This system was visited by the USS Voyager on stardate 48734.