The USS Philadelphia was a 24th century Federation starship operated by Starfleet.
Alfonse Pacelli was assigned on stardate 40127.8 to this ship, which was named in his personnel file. (TNG: "Eye of the Beholder")
This starship was only mentioned in writing.
This starship was listed with other real starships in the ship list from the Star Trek Encyclopedia (4th ed., vol. 2, p. 332).