Sefalla Prime was the prime planet in its star system. This planet was located near Draylon II.

When Commander Sisko and Major Kira were considering Draylon II as a possible site for relocating the Skrreea population in 2370, they noted that the planet was near Sefalla Prime. (DS9: "Sanctuary")

This planet was only mentioned in dialogue.
According to, Sefalla Prime, in orbit of the star Sefalla, was located in the Sefalla system, which was located in the Bajoran sector. [1]; [2]