Cardassia I was the first planet in the Cardassian system, in the Alpha Quadrant. The planet was affiliated with the Cardassian Union.
In 2375, the location of Cardassia was labeled on a tactical map that was displayed in the wardroom of Deep Space 9. (DS9: "When It Rains...", okudagram)
Later that year, the position and orbital path of Cardassia I was illustrated on a tactical map that was displayed in the wardroom of Deep Space 9. (DS9: "The Dogs of War", okudagram)
"car-DASS-ee-uh" was the pronunciation for this planet's name from the script pronunciation guide for "Tribunal".