Gamma Argus II was a planet located somewhere in the space of the galaxy's Alpha or Beta Quadrants, the second planet in orbit of the Gamma Argus star system. A civilization of natives originated on this world. In the 24th century, the natives maintained a pre-warp drive society that, in the 2360s decade, made the planet subject to the Federation's Prime Directive.
In the year 2364, starships Callisto and Mustang were ordered to observe the societal evolution of this world. Captains Goldberg and Arakaki were granted discretion as agents of the Federation to decide whether first contact with the natives was warranted. When Captain Jean-Luc Picard ordered Data to review Starfleet orders for inconsistencies in that same year, this instruction was one of the pieces of information that was viewed. (TNG episode: "Conspiracy")