Unroth III was a Romulan colony world in the Unroth system in the Onias Sector near the border with the Cardassian Union. (ST reference: Star Charts, ENT novel: The Good That Men Do)

During the Dominion War, Dominion forces planned an attack on the colony upon discovering that the planet's long-range scanners were under repair. (DS9 episode: "Strange Bedfellows")