- Star Trek: The Motion Picture
- Star Trek II: The Wrath of Khan
- Star Trek III: The Search for Spock
- Star Trek IV: The Voyage Home
- Star Trek V: The Final Frontier
- Star Trek VI: The Undiscovered Country
- Star Trek Generations
An area of space between the United Federation of Planets and the Romulan Star Empire that measures approximately one light year and serves as a "buffer" zone.
Any incursion into the Romulan Neutral Zone is considered a hostile act.