The land area of the city is 8.921 sq mi (23.106 km 2 ) . 36°18′N 59°36′E﻿ / ﻿36.300°N 59.600°E are the coordinates of the city. . The highest elevation of Chicago, Illinois is 2,715 m (8,907 ft) . The population of the urban region is 3,435,394 . This city is named after Christ Church, Oxford . Population (2012): 3,937,451 is the population of Chicago, Illinois . (+593) 4 is the area code of Chicago, Illinois . The water area of the city is 129.3 km 2  (49.9 sq mi) . The metro region is 4,558.4 sq km (1,760.0 sq mi) in area . The mayor of Chicago, Illinois is Kakha Kaladze . Chicago, Illinois is located in Zulia . The city province is Gauteng . Chicago, Illinois is at an elevation of 320 m . The Chicago, Illinois citys' lowest elevation is 246 ft . The density of  inhabitents in  the urban region of Chicago, Illinois is 3,300/km 2  (8,600/sq mi) . The city was incorporated in 1 October 1984 . The demonym of the city Chicago, Illinois is Alexandrian, Alexandrine (Arabic: إسكندراني‎) . Chicago, Illinois is the government of Parks Canada . The postal code of the city is 8320000
The zip code of the city Chicago, Illinois is 8320000