Nizhneudinsk (Russian: Нижнеу́динск, IPA: [nʲɪʐnʲɪˈudʲɪnsk]; Buryat: Доодо-Үдэ, Doodo-Üde) is a town and the administrative center of Nizhneudinsky District of Irkutsk Oblast, Russia, located on the Uda River (Yenisei's basin), 506 kilometers (314 mi) northwest of Irkutsk, the administrative center of the oblast.

[citation needed] Nizhneudinsk was so named to distinguish it from Verkhneudinsk (now Ulan-Ude).

[6] The town stands on the Trans-Siberian Railway and is served by a small airport, ICAO code UINN.

[11] In 1987, the 91st Motor Rifle Division was withdrawn from Mongolia and arrived at Nizhneudinsk.

Later that year it became a Territorial Education Center, and then a Base for Storage of Weapons and Equipment.