High Quality Content by WIKIPEDIA articles! Russians (Bulgarian: руснаци, rusnatsi) form the fourth largest ethnic group in Bulgaria, numbering 9,978 according to the 2011 census, and mostly living in the large urban centres, such as Sofia, Plovdiv, Varna and Burgas. Although the largest wave of Russian settlers (White Guards) arrived following the events surrounding the October Revolution and the Russian Civil War, compact groups of Russians had been living in Bulgaria for centuries before that.