 The city area code is +374 10 . Hanoi is the government of National Park Service . On March 6, 1836 (city) the city was incorporated . The land area of the city is 11,609.91 km 2  (4,482.61 sq mi) . The density of  people in  the metro region of Hanoi is 2,813/km 2  (7,290/sq mi) . The water area of the city is 4.46 sq km  (1.72 sq mi) . The density of  inhabitents in Hanoi is 5,300/km 2  (14,000/sq mi) . The lowest elevation of Hanoi is 620 ft . The city Hanoi demonym is Barranquillero/a . Tang Liangzhi is the mayor of Hanoi . The population of the metro region is Populations (2019): 3,731,447 . The area of the city is 385.8 sq mi (999.3 sq km ) . Hanoi is at an elevation of 7380 ft . The area of the urban region is 14.0 sq mi (36 km 2 ) . 4,800/km 2  (12,000/sq mi) is the density of people in  the urban region of Hanoi . The postal code of the city is 130000 . This city is named after Confluence of Grand River and Gunnison River
385.8 sq mi is covered by the city