The Gamma Canaris region was a region of space. This region was located near the inhabited planet Epsilon Canaris III. There was an asteroid belt in the region, that consisted of approximately 7,000 bodies of sizes running from types A to N. 34 percent of which had atmospheres of types H to M. (TOS: "Metamorphosis")
In 2293, the location of Gamma Canaris N 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)
In the early 22nd century, a non-corporeal lifeform native to this region, known as the Companion, discovered the disabled warp ship of the Human inventor of Earth's warp drive, Zefram Cochrane. The entity brought the ship and its pilot Cochrane safely down to Gamma Canaris N, a planetoid in the asteroid belt. The Companion rejuvenated the 87 year old inventor and terraformed the planetoid to sustain Cochrane's life.
In 2267, while transporting the terminally-ill Commissioner Nancy Hedford from Epsilon Canaris III to the USS Enterprise, shuttlecraft Galileo was pulled off course by the Companion and forced to land on its homeworld. Cochrane had told the entity that he would die of loneliness if he didn't have contact with other humans. The Companion merged with Commissioner Hedford moments before her death and Cochrane remained with her on the planetoid. James T. Kirk promised Cochrane that he would not tell Starfleet that they had discovered him or of what had happened on the planetoid. (TOS: "Metamorphosis")