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