Located to the north of the Southern Highway, the Riolta Plains led to Mt. Plegate in the west and the Holy City of Thaksis to the north.
In HIY 300 the Company was ambushed by the Grubs at this location when pursuing Aaron Barcai to Mt. Plegate. Locked in a stalemate, the Company would be able to proceed only after the intervention of Jagwan's scalehorde troops.
In HIY 100, Syldis and Nolbanos Nobilious came to the Riolta Plains to investigate the possibility of a [[Teras Pharma] sighting, passing on their skills as Starbearers in the process.
In HIY 200, Suomjin introduced the Company to the fletcher Mephitis there. The plains at that time held contaminated hot spring water that Mephitis used for her poisoned arrows.