Starbase 12

Starbase 12 is a Federation starbase and is located in orbit of the Rhodes colony in the Gamma 400 system of the Mutara sector. Starbase 12 is one of the most important outposts in the Federation as it is in reach of both the Klingon and Romulan empires. (TOS episode: "Space Seed" and TNG novel: Ship of the Line).