It used to be part of the Soviet Union, and the most dominant of its fifteen republics, but the band broke up in the early 1990s. Or so we ''think''.
IDW comics continuity
An ongoing separatist movement in the state of Brasnya was being manipulated by the Decepticons for their own ends, by means of artificial human "facsimiles". Russian and seperatist forces were manipulated into conflict, which could have exploded into a major war if the battle hadn't disrupted by cars fighting space shuttles and the presence of giant warring robots.
After being directly spoken to by one robot, the Russian forces stood down and withdrew.
In an alternate reality, the Decepticon invasion caused Russia to buddy up with NATO and advocate nuclear strikes on Decepticon-held America. It didn't work out well...
Bulkhead and Breakdown were fighting in Russia, until Bulkhead was knocked unconscious by Breakdown while the Decepticon was disabled by a missile shot from a helicopter by MECH. MECH's first base is located in Russia while its second base is somewhere around Nevada.