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