de Laure belt
The de Laure belt was a spatial region that was located somewhere in the Alpha or Beta Quadrant. One of the systems in this belt was the Tau Cygna system. The belt had high concentrations of hyperonic radiation. This region was 5,000 or more light years from Sol.
The USS Enterprise-D was on a mission in the belt in early 2366 to evacuate a Human colony from Tau Cygna V as the planet was claimed by the Sheliak Corporate. (TNG: "The Ensigns of Command")
In the Star Trek: Star Charts ("United Federation of Planets II"), Tau Cygna and by inference, the de Laure belt, was located in the Alpha Quadrant.