A Gamma Quadrant planet that the Vorta Eris claims as her conquered homeworld when she poses as a fugitive from the Dominion in The Jem'Hadar.
Kurill Prime is mentioned in The Jem'Hadar, the finale of Deep Space Nine's second season (2370).
Sisko and Quark are captured by Jem'Hadar soldiers during a camping trip in the Gamma Quadrant and meet a fellow prisoner, Eris. She says she comes from Kurill Prime, a world the Dominion took over after its people refused an offer to join, and that the Jem'Hadar carried out the conquest. She is the first to describe the Dominion's rule by the unseen Founders.
Her story is at least partly a pretence. Quark discovers that the collar said to block her telekinetic powers is a fake, and Eris, exposed as a Dominion agent, beams away. Whether Kurill Prime is truly the Vorta home is left unstated on screen.