Moscow is designated as a city.
A capital city ( or simply capital ) is the municipality exercising primary status in a country , state , province , or other region , usually as its seat of government . Moscow is the capital and most populous city of Russia , with 13.2 million residents within the city limits and 17.8 million within the urban area . By broader definitions Moscow is among the world 's largest cities , being the 14th largest metro area , the 18th largest agglomeration , the 15th largest urban area , and the 11th largest by population within city limits worldwide . Moscow has acquired a number of epithets , most referring to its size and preeminent status within the nation : The Third Rome , The Whitestone One , The First Throne , The Forty Forties , and The Hero City .