Rostov Oblast is a federal subject of Russia, located in the Southern Federal District. The oblast has an area of 100,967 square kilometers (38,984 sq mi) and a population of 4,200,729, making it the sixth most populous federal subject in Russia. Its administrative center is the city of Rostov-on-Don, which also became the administrative center of the Southern Federal District in 2002.

Rostov-on-Don is a port city and the administrative centre of Rostov Oblast and the Southern Federal District of Russia. It lies in the southeastern part of the East European Plain on the Don River, 32 kilometers (20 mi) from the Sea of Azov, directly north of the North Caucasus. The southwestern suburbs of the city lie above the Don river delta. Rostov-on-Don has a population of over one million people and is an important cultural centre of Southern Russia.