Quadrant 904 was a region of space. This quadrant was located nine hundred light years from Earth, and six days from the Beta VI colony at warp 3.
This quadrant was the location of a star desert. In 2267, the USS Enterprise entered this quadrant on a supply run to Beta VI, and encountered the planet Gothos. (TOS: "The Squire of Gothos")
In 2328, the Quadrant 904 Central Station was a point of embarkation and destination for commercial transports. (TNG-R: "Inheritance")