Lazon II was the second planet in the Lazon planetary system. This system was located in Cardassian space. It was the site of a labor camp, where Thomas Riker was to be imprisoned for the remainder of his life. (DS9: "Defiant")
According to the Star Trek: Star Charts (pg. 46), the Lazon system was located in or near Cardassian space, in the Alpha Quadrant. This system was a single star system. Primary was a Class A star with a magnitude of +3, which was ten times brighter than Sol.