The Cardassian system was an inhabited planetary system. This system was located in the Cardassian sector. This sector was a region of space in the Alpha Quadrant. The system consisted of a primary and five named planets. One of the planets, Cardassia Prime (Cardassia II), was inhabited by the Cardassians, a warp capable species. This planet was the capital of the Cardassian Union. (DS9: "Explorers") The planets Cardassia III, Cardassia IV, and Cardassia V were colonized by the Cardassians. (DS9: "The Homecoming", "Shadowplay", "Prophet Motive") In 2375, the Dominion began their withdrawal to Cardassia Prime during the waning days of the Dominion War. The Allied Forces, or Allied Fleets, planned a risky and costly military operation to end the war by penetrating the system and engaging the forces stationed in orbit of Cardassia Prime. (DS9: "The Dogs of War")
It was never stated in the canon if Cardassia I was an inhabited planet.
"Tactical Display 7624N" was reproduced for the Star Trek: Star Charts, and appeared on page 49.
According to this same book (pgs. 36, 42-43), the system primary was named Cardassia. Cardassia was a K class star with a magnitude of -1, which was a hundred times brighter than Sol. There were eight planets in the system, four of which were inhabited, and two asteroid belts. The system was visited by a Bajoran solar-sail vessel in 1571. Distance between Bajor and Cardassia was 5.25 light years.