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Cook County

Cook County, Illinois
County
The century-old, neoclassical County and City Hall building (left) in the Chicago Loop houses the County Board chambers and administrative offices. The Chicago Picasso stands in front of Daley Center, the home of Cook County Circuit Court.
The century-old, neoclassical County and City Hall building (left) in the Chicago Loop houses the County Board chambers and administrative offices. The Chicago Picasso stands in front of Daley Center, the home of Cook County Circuit Court.
Flag of Cook County, Illinois
Flag
Official seal of Cook County, Illinois
Seal
Map of Illinois showing Cook County
Map of Illinois showing Cook County
Illinois's location in the United States
Illinois's location in the United States
Coordinates: 41°48′N 87°43′W / 41.800°N 87.717°W / 41.800; -87.717Coordinates: 41°48′N 87°43′W / 41.800°N 87.717°W / 41.800; -87.717
Country United States United States
State Illinois Illinois
Region Northern Illinois
Metro area Chicago Metropolitan
Incorporated January 15, 1831
Named for Daniel Cook
County seat Chicago
Largest city Chicago
Incorporated municipalities
Government
 • Type County
 • Body Board of Commissioners
 • Board President Toni R. Preckwinkle (D)
 • County Board 17 commissioners
Area
 • County 1,635 sq mi (4,230 km2)
 • Land 945 sq mi (2,450 km2)
 • Water 690 sq mi (1,800 km2)
 • Metro 10,874 sq mi (28,160 km2)
Area rank 6th largest county in Illinois
Highest elevation 950 ft (290 m)
Lowest elevation 580 ft (180 m)
Population (2010)
 • County 5,194,675
 • Estimate (2015) 5,238,216
 • Rank 1st largest county in Illinois
2nd largest county in U.S.
 • Density 5,530/sq mi (2,140/km2)
 • Metro 9,522,434
Time zone Central (UTC-6)
 • Summer (DST) Central (UTC-5)
ZIP Code prefixes 600xx thru 608xx
Area codes 224/847, 312/872, 773/872, 708
Congressional districts 1st, 2nd, 3rd, 4th, 5th, 6th, 7th,
8th, 9th 10th and 11th
FIPS code 17-031
GNIS feature ID 1784766
Interstates

I-55.svg I-57.svg I-80.svg I-88.svg Chicago Skyway logo.svg I-90.svg I-94.svg I-190.svg I-290.svg I-294.svg I-355.svg


U.S. Routes

US 6.svg US 12.svg US 14.svg US 20.svg US 30.svg US 34.svg US 41.svg US 45.svg US 66 (historic).svg


State Routes

Illinois 1.svg Illinois 7.svg Illinois 19.svg Illinois 21.svg Illinois 25.svg Illinois 38.svg Illinois 43.svg Illinois 50.svg Illinois 53.svg Illinois 56.svg Illinois 58.svg Illinois 59.svg Illinois 62.svg Illinois 64.svg Illinois 68.svg Illinois 72.svg Illinois 83.svg Illinois 110.svg Illinois 171.svg Illinois 390.svg Illinois 394.svg


Airports

Chicago O'Hare International
Chicago Midway International
Chicago Executive
Lansing Municipal
Schaumburg Regional


Waterways

Lake MichiganChicago River
Chicago Sanitary and Ship Canal
Calumet RiverDes Plaines River
North Shore Channel


Amtrak stations

Chicago Union Station
GlenviewHomewood
La GrangeSummit


Public transit Chicago Transit Authority (CTA)
MetraPaceSouth Shore Line
Website www.cookcountyil.gov
Chicago, Illinois
Climate chart ()
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Average max. and min. temperatures in °F
Precipitation totals in inches
Source: The Weather Channel