Novocherkassk is a city in Rostov Oblast, Russia, located near the confluence of the Tuzlov and Aksay Rivers, the latter a distributary o…Novocherkassk is a city in Rostov Oblast, Russia, located near the confluence of the Tuzlov and Aksay Rivers, the latter a distributary of the Don River. Novocherkassk is best known as the cultural capital of the Cossacks, and as the official capital of the Don Cossacks. Population: 168,746 ; 170,822 ; 187,973.