Cardassia I (innermost planet) on Tactical Display 7624N
Cardassia I was the first planet in the Cardassian system. This system was located in the Cardassian sector, which was a region of space in the Alpha Quadrant. The planet was larger than Cardassia II (Cardassia Prime), but smaller than Cardassia III. The planet was affiliated with the Cardassian Union. (DS9: "The Dogs of War")
According to the Star Trek: Star Charts, Cardassia I was a B class planet.