"Star desert" was a term used to describe an area of space with zero density and no change in gravimetric readings. Such a void existed approximately nine hundred light years from Earth, containing Quadrant 904.
In 2267, the USS Enterprise attempted to cross this area while en route to the colony at Beta VI on a mission to deliver supplies. Their journey was interrupted, however, by the intervention of the extremely powerful entity Trelane, who used the opportunity to create the planet of Gothos in this area. (TOS: "The Squire of Gothos")