M-class planet considered by many to be one of the most beautiful in the galaxy, colonized by humans in the 22nd century, later becoming a Federation world, and used as a freighting line base in the region. Deneva has served as a key supply station for many Earth cargo ships, including the E.C.S. Horizon, for at least two centuries. Freighters would make regular trips from Deneva carrying supplies to the nearby asteroid belt for the miners stationed there, and bringing cargo out. Montgomery Scott was an engineering advisor on a couple of those freighter runs.
Deneva boasted a population of over 1 million by the 23rd century. Aurelan and George Samuel Kirk were among the colonists, though they were victims in 2267 of an infestation of neural parasites that caused mass insanity and many deaths in the colony. (Their son Peter survived.) Sam's brother James Kirk of the U.S.S. Enterprise managed to talk with Aurelan right before she died, and learned that the large single-celled creatures controlled the actions of their human hosts with intense pain. An infested colonist had killed himself trying to drive the organism from his body by flying himself into the Denevan sun, and that led Enterprise personnel to learn that the parasites were adversely affected by ultraviolet radiation. The crew placed 210 satellites around the planet to bombard the surface with intense ultraviolet radiation, and succeeded in eradicating the infestation.
In the 24th century, Denevan crystals were considered contraband material, its possession or sale prohibited by Federation law. This did not stop Quark from selling Denevan crystals to a Nausicaan businessman for a tidy profit on Deep Space Nine.