Omsk is the administrative center and largest city of Omsk Oblast, Russia. It is situated in southwestern Siberia and has a population of over 1.1 million. Omsk is the third largest city in Siberia after Novosibirsk and Krasnoyarsk, and the twelfth-largest city in Russia. It is an important transport node, serving as a train station for the Trans-Siberian Railway and as a staging post for the Irtysh River.

Tara is a town in Omsk Oblast, Russia, located at the confluence of the Tara and Irtysh Rivers at a point where the forested country merges into the steppe, about 300 kilometers (190 mi) north of Omsk, the administrative center of the oblast. Population: 27,318 (2010 Russian census); 26,888 (2002 Census); 26,152 (1989 Soviet census).