Simperia was a planet in Cardassian space, and the site of a base of the Cardassian Liberation Front during the latter half of the Dominion War.
The base was one of eighteen destroyed by Dominion and Breen forces in late 2375. (DS9: "The Dogs of War")
This planet was only mentioned in dialogue.
According to the script
, Simperia was pronounced as "sem-PAIR-ee-ah".