The area of the urban region is 11,609.91 km 2  (4,482.61 sq mi) . The density of  people in Tianjin is 1,300/km 2  (3,400/sq mi) . Zhang Guoqing is the mayor of Tianjin . Tianjin is located in People's Republic of China . The land area of the city is 11,609.91 km 2  (4,482.61 sq mi) . The city Tianjin demonym is Tianjinese , Tianjiner . The city water area is 186 km 2  (72 sq mi) . The postal code of the city is 3000 00 -  3019 00 . The area of the metro region is Area: 5,609.9 km2 (2,166.0 sq mi)The population of the metro region is Population: 12,491,300 (2016) . The coordinates of the city are 39°08′N 117°11′E﻿ / ﻿39.133°N 117.183°E . 22 is the area code of Tianjin
72 sq mi area of the city Tianjin is water