Talos star group
Talos III was the inhabited third planet of the Talosian system. This system was located within the Talos star group, which was located in the Alpha Quadrant. This ringed world had no moons. The planet was located 2.5 astronomical units from the binary stars of Talos A and Talos B.
Sometime before stardate 8130, materials from Talos III were sent in a container to Regula. (TOS: "The Cage", "The Menagerie, Part I"; Star Trek II: The Wrath of Khan; Star Trek VI: The Undiscovered Country, production art)
The planet was never mentioned in dialog; this name came from a map of the Talosian system. Talos III was identified again on a blue cargo-container tube seen in The Wrath of Khan. In "The Explored Galaxy" the location of Talos was depicted between the Tholian Assembly and Romulus. Both locations were identified in DS9: "Call to Arms" as being located in the Alpha Quadrant.
According to Star Trek: Star Charts, Talos III was a L-class planet. In 2378, Talos III was located in or near Federation space, in the Alpha Quadrant. (Pgs. 40-41, "United Federation of Planets III")