Alpha Onias III was the uninhabited third planet of the Alpha Onias system, in the Beta Quadrant. This system was located in the Onias sector, a region of space near the Romulan Neutral Zone. Although it was class M, Starfleet survey teams listed Alpha Onias III as barren and inhospitable with an atmosphere containing high, but non-toxic, levels of volcanic gases, including sulfur dioxide, methane, and hydrogen sulfide.