Bayanday (Russian: Баяндай) is a rural locality (a selo) and the administrative center of Bayandayevsky District of Ust-Orda Buryat Okrug, Irkutsk Oblast, Russia.

Population: 2,672 (2010 Census);[3] 2,874 (2002 Census);[4] 3,383 (1989 Soviet census).

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