Moscow is the capital, the most populous city, and the most populous federal subject of Russia. The city is a major political, economic, cultural, scientific, religious, financial, educational, and transportation center of Russia and the continent. Moscow is the northernmost megacity on Earth (but not the coldest), the most populous city in Europe, and the fifth largest city proper in the world. Its population, according to the results of the 2010 Census, is 11,503,501. Based on Forbes 2011, Moscow had 79 billionaires, displacing New York City as the city with the greatest number of billionaires.

Moscow is situated on the Moskva River in the Central Federal District of European Russia. In the course of its history the city has served as the capital of a progression of states, from the medieval Grand Duchy of Moscow and the subsequent Tsardom of Russia to the Soviet Union. Moscow is the site of the Moscow Kremlin, an ancient fortress that is today the residence of the Russian President and of the executive branch of the Government of Russia. The Kremlin is also one of several World Heritage Sites in the city. Both chambers of the Russian parliament (the State Duma and the Federation Council) also sit in Moscow.

The city is served by an extensive transit network, which includes four international airports, nine railroad terminals, and one of the deepest underground tubes in the world, the Moscow Metro, second only to Tokyo in terms of ridership and recognized as one of the city's landmarks due to the rich and varied architecture of its 185 stations.

Over time, 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 (????? ???????). In old Russian the word "?????" (forty) also meant a church administrative district, which consisted of about forty churches.The demonym for a Moscow resident is Moskvitch, rendered in English as Muscovite.