The Hugora Nebula is a stellar cloud that was located on the Federation's side of the Demilitarized Zone.
As part of an ambush on Maquis ships planned in 2370, Federation starships hoped to use the nebula as cover from Maquis sensors. (TNG: "Preemptive Strike")
According to the Star Trek: Star Charts, on page 47, the Hugora Nebula was located in the Alpha Quadrant.