Greater Beirut (Arabic: بيروت الكبرى; French: Grand Beyrouth) is the urban agglomeration comprising the city of Beirut (Beirut Governorate) and the adjacent municipalities over the Mount Lebanon Governorate. It does not constitute a single administrative unit. Greater Beirut geographically stretches south to the Damour River in the Chouf District until it reaches the "Nahr al-Kalb" river in the Keserwan District in the north. It also comprises many towns and cities in the mountains in the Aley District, Baabda District and Metn District Districts, most notably being the cities of Baabda, Beit Mery, Bchamoun and Mtaileb. The conurbation spreads south, east, and north of Beirut city. To the west, the Eastern Mediterranean Sea serves as a natural boundary.