[2] The settlement of Ust-Ordynsky is the autonomous okrug's administrative center and its most populous inhabited locality.

In a referendum held on April 16, 2006, the majority of residents in Irkutsk Oblast and Ust-Orda Buryat Autonomous Okrug agreed to the unification of the two regions.

The merger was approved by an absolute majority of the electorate: by 89.77% in Irkutsk Oblast and by 97.79% in Ust-Orda Buryatia.

[3][4] The okrug is divided into six administrative districts: Of the 135,327 residents (as of the 2002 Census), 38 (0.02%) chose not to specify their ethnic background.

Of the rest, residents identified themselves as belonging to 74 ethnic groups, including Russians (54.4%), Buryats (39.6%), Tatars (3%) and Ukrainians (0.96%)