Ust-Orda Buryat Okrug, or Ust-Orda Buryatia, is an administrative division of Irkutsk Oblast, Russia. It was a federal subject of Russia from 1993 to January 1, 2008, when it merged with Irkutsk Oblast. It also had autonomous okrug status from September 26, 1937 to 1993. Prior to the merger, it was called Ust-Orda Buryat Autonomous Okrug. It is one of the two Buryat okrugs in Russia, the other one is Agin-Buryat Okrug in Zabaykalsky Krai.