Gamma Trianguli was an inhabited planetary system in the Gamma Trianguli sector of the Alpha Quadrant. This single star system had at least six planets, including Gamma Trianguli IV and Gamma Trianguli VI.
In 2293, the location of Gamma Trianguli in the Milky Way Galaxy was labeled in a star chart that was in Captain James T. Kirk's quarters aboard the USS Enterprise-A. (Star Trek VI: The Undiscovered Country, okudagram; ENT: "In a Mirror, Darkly, Part II", product art)
In 2399, the location of Gamma Trianguli was labeled in a star chart that was in Fleet Admiral Kirsten Clancy's office at Starfleet Headquarters. This system was in neutral space. (PIC: "Maps and Legends")