Quarra was a class M planet and homeworld to the Quarren civilization. The planet was located in the Delta Quadrant, circa 30,000 light-years from Sol. (VOY episode: "Workforce", STO mission: "Sphere of Influence")
The civilization on Quarra was warp-capable. Because the Quarren were deficient in technological automation, they attacked starships using radioactive mines, capturing and brainwashing their crews and employing them as workforce. In 2377, the Quarren abducted the crew of USS Voyager and indoctrinated them. Their efforts failed, however, and the Voyager crew broke out and made the Quarren machinations public. (VOY episode: "Workforce")
By 2409, the Iconians held a Level 6 surveillance in place. The planet was under constant surveillance by the Solanae servitor species. Life data feeds were transmitted to Storage Facility Z98 in subspace. The Iconians considered the Quarren method of capturing aliens to add to their workforce interesting but inefficient. The Iconians considered to cooperate with them, alleviating their manpower problems in return for detailed information about their indoctrination techniques. Quarra was considered a potential servitor planet in a revived Iconian Empire.
When Ambassador Worf of the extent of Iconian surveillance in the Milky Way Galaxy, he express surprise at the fact that Iconian influence reached the Delta Quadrant. (STO mission: "Sphere of Influence")