The location of Talos on "The Explored Galaxy" star chart
Talos III was the ringed third planet of the Talosian system within the Talos star group. The planet was located 2.5 astronomical units from the binary stars of Talos A and Talos B. (TOS: "The Cage", "The Menagerie, Part I", production art)
Sometime before stardate 8130, in 2285, materials from Talos III were sent in a container to Regula. (Star Trek II: The Wrath of Khan)
In 2293, the location of the Talos system in the Milky Way Galaxy was depicted on the Federation star chart The Explored Galaxy. This chart was first seen on aboard the starship USS Enterprise-A. In the 2360s, the chart was seen again aboard the USS Enterprise-D, the outpost Starbase 173, and at Starfleet Headquarters on Earth. (Star Trek VI: The Undiscovered Country, production art; TNG: "Conspiracy", "The Measure Of A Man", "The Emissary")