Nikolayevsk is a town and the administrative center of Nikolayevsky District in Volgograd Oblast, Russia, located on the left shore of the Vā¦Nikolayevsk is a town and the administrative center of Nikolayevsky District in Volgograd Oblast, Russia, located on the left shore of the Volga River. Population: 15,075 ; 16,125 ; 16,469.