The Galen system was a star system in the Alpha Quadrant. It contained five planets, including the inhabited warp-capable world of Galen IV. By 2259, the United Federation of Planets had established first contact with this system and could visit it freely.
Nearby inhabited star systems included the Talar, Kiley, Gamma Trianguli, Alpha Majoris, Scalos, and Algol systems.
In 2259, the location of this system was labeled on a stellar cartography chart that was seen on the USS Enterprise's ready room viewscreen. This system's symbol had a blue color, indicating that it was affiliated with the United Federation of Planets. (SNW: "Strange New Worlds", "Children of the Comet")
This star system was only mentioned in writing.
In the episode "Children of the Comet", there were two locations named Galen. One of the Galen system's symbols had an orange color.