Rome is the capital of Italy and of the Lazio region. With 2.9 million residents in 1,285 km2 (496.1 sq mi), it is also the country’s largest and most populated comune andfourth-most populous city in the European Union by population within city limits. The Metropolitan City of Romehas a population of 4.3 million residents. The city is located in the central-western portion of the Italian Peninsula, within Lazio (Latium), along the shores of Tiberriver. Vatican City is an independent country within the city boundaries of Rome, the only existing example of a country within a city: for this reason Rome has been often defined as capital of two states.