Toranius Prime was the inhabited prime planet in its star system. This system was located in the Delta Quadrant.
In the memories of the Nakan massacre preserved by the memorial monument on Tarakis, Commander Saavdra proposed to his soldiers a week on Toranius Prime after their mission to relocate the Nakan colonists was completed. Saavdra described it as "paradise" compared to Tarakis. (VOY: "Memorial")
This planet was only mentioned in dialogue.