- For the mirror universe counterpart, see Ilia (mirror).
Ilia was a female Deltan who was a Starfleet officer who lived during the 23rd century.
With the rank of lieutenant, Ilia served as navigator aboard the newly refitted USS Enterprise under Rear Admiral James T. Kirk. In 2273, Ilia was absorbed by V'Ger and listed as missing in action.
Ilia had been involved in a romantic relationship with Captain Willard Decker some time prior. (TOS movie, novelization & comic adaptation: Star Trek: The Motion Picture; TOS comics: "The Motion Picture", "V'Ger", "Evolutions")