Starbase 16 was a Federation starbase that was operational by the mid-23rd century, located near the Tycho star system. (TOS - My Brother's Keeper novel: Constitution)
In 2257, Lieutenant James T. Kirk had the USS Farragut divert to Starbase 16 for repairs following the death of 200 crewmembers after the encounter with a dikironium cloud creature. (TOS - My Brother's Keeper novel: Constitution)
In an alternate timeline, the USS Enterprise docked at Starbase 16 for shore leave in 2269, after successfully stopping a second Federation-Klingon war. (TOS novel: Spock Must Die!)
In 2269, the Great Starship Race to Gullrey was launched from Starbase 16. Following the race, the Enterprise docked at the base for structural repair following a high-warp pursuit of the ChR Red Talon. (TOS novel: The Great Starship Race)
Not long after the V'Ger incident in mid-to-late 2273, the USS Enterprise repatriated a rescued Federation film archivist and a captured alien thought-enhancer to Starbase 16, following a failed attempt by the Klingon Empire to take control of the newly-refitted starship using the latter technology. (TOS comic: "The Haunting of the Enterprise!")
In 2279, the Belle Terre Colonial Expedition was also launched from Starbase 16, with the Enterprise leading a large group of colonization vessels to Occult IV in Cluster Z-80. (TOS - New Earth novel: Wagon Train to the Stars)
