(often spelled Gamma Hydra
) is a spectral class G8 star 130 light years from the Sol system.
It was near Romulan space and Starbase 10. (TOS: "The Deadly Years") The starships Exeter and John F. Kennedy helped establish the colony on Gamma Hydra IV in 2254. (Orion Press: The Mindsweeper)
In 2267, USS Concordat distinguished herself in action against Klingons in the Gamma Hydra sector. (TrekRPGNet)
In the Kobayashi Maru scenario undertaken by command cadets at Starfleet Academy, the purported location of the ship is in "Gamma Hydra, Section 10." (Star Trek II: The Wrath of Khan)
In 2381, during the short conflict between the Romulan Empire and the Federation, Romulan forces broke through the lines and attacked the fourth planet in this system, They then landed troops to occupy the colony there. Starfleet soon retaliated by sending two Marine Expeditionary Brigades, and the entire Second Fleet to retake the planet.(Star Trek: New Order: ...The Hardest Part)