Naples is the regional capital of Campania and the third-largest city of Italy, after Rome and Milan, with a population of 908,082 within the ci…Naples is the regional capital of Campania and the third-largest city of Italy, after Rome and Milan, with a population of 908,082 within the city's administrative limits as of 2025, while its province-level municipality is the third most populous metropolitan city in Italy with a population of 2,958,410 residents, and its metropolitan area stretches beyond the boundaries of the city wall for approximately 30 kilometres. Naples also plays a key role in international diplomacy, since it is home to NATO's Allied Joint Force Command Naples and the Parliamentary Assembly of the Mediterranean.