Ust-Orda Buryat Okrug (Russian: Усть-Орды́нский Буря́тский о́круг; Buryat: Усть-Ордын Буряадай округ Ust'-Ordyn Burjaadaj okrug), or Ust-Orda Buryatia, is an administrative division of Irkutsk Oblast, Russia. It was a federal subject of Russia (an autonomous okrug of Irkutsk Oblast) from 1993 to January 1, 2008, when it merged with Irkutsk Oblast (it also had autonomous okrug status from September 26, 1937 to 1993, but the autonomous okrug was not the federal subject in conformity with the Soviet Constitution). Prior to the merger, it was called Ust-Orda Buryat Autonomous Okrug (Усть-Орды́нский Буря́тский автоно́мный о́круг).
It has an area of 22,138.1 square kilometers (8,547.6 sq mi). Population: 125,206 (2010 Census preliminary results).
The settlement of Ust-Ordynsky is the autonomous okrug's administrative center and its most populous inhabited locality.
Read more about Ust-Orda Buryat Okrug: Merger, Administrative Divisions