An unnamed planet located in the space of the galaxy's Alpha or Beta Quadrant, near the Romulan Neutral Zone, was the home of the Federation's Starbase 10.
History and specifics[]
The world was habitable, and the ruins of an old civilization, the Kundiawaq, surrounded the Starfleet base. An orbital space station facility that was part of the starbase was also positioned at this world. (TOS - Annual comic: "The Final Voyage"; TOS comic: "The Argon Affair!"; TOS episode & Star Trek 7 novelization: The Deadly Years)
It was located in Starfleet Intelligence sector 3 near the Triangle sector. (FASA RPG module: Star Fleet Intelligence Manual)