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Cook County, Illinois
—  County  —


Map of Cook County
Illinois's location in the United States
Country United States
State Illinois
Region Northern Illinois
Metro area Chicago metropolitan area
Incorporated January 15, 1831
Named for Daniel Cook
County seat Chicago
Incorporated cities 130
 • President Toni R. Preckwinkle
 • Total 1,635 sq mi (4,230 km2)
 • Land 946 sq mi (2,450 km2)
 • Water 689 sq mi (1,780 km2)
Population (2010) 5,194,675
 • Density 5,491.3/sq mi (2,120.2/km2)
Time zone Central Standard Time (UTC-6)
 • Summer (DST) Central Daylight Time (UTC-5)
Website [1]

Cook County is a county in the U.S. state of Illinois, with its county seat in Chicago. It is the second most populous county in the United States after Los Angeles County. The county has 5,194,675 residents,[1] which is 40.5% of all Illinois residents. Cook County's population is larger than that of 29 individual U.S. states and the combined populations of the seven smallest US states.[2] There are over 130 incorporated municipalities in Cook County, the largest of which is Chicago, which makes up approximately 54% of the population of the county. That part of the county which lies outside of the Chicago city limits is divided into 30 townships. Geographically the county is the fifth largest in Illinois by land area and shares the state's Lake Michigan shoreline with Lake County. Cook County is mainly urban and densely populated, containing the city of Chicago and many suburbs. However, there are still some semi-rural areas near the outskirts of the county.


Cook County was created on January 15, 1831 out of Putnam County by an act of the Illinois State Legislature. It was the 54th county established in Illinois and was named after Daniel Cook, one of the earliest and youngest statesmen in Illinois history, who served as the second U.S. Representative from Illinois and the first Attorney General of the State of Illinois. Shortly thereafter, in 1839, DuPage County was carved out of Cook County.

Government and politics[]

The century old, neoclassical County and City Hall building (left) in the Chicago Loop houses the County Board chambers and administrative offices

Cook County's current County Board president is Toni Preckwinkle. The county has by far more Democratic Party members than any other Illinois county, and is one of the most Democratic counties in the United States. It has voted only once for a Republican candidate in a Presidential election in the last forty years, when county voters preferred Richard Nixon to George McGovern in 1972.

The Cook County Democratic Organization is one of the best known political machines in American history. Commonly called the "Chicago Democratic machine", or simply the "Chicago Machine", the machine has dominated Chicago politics since the 1930s when it supplanted a Republican machine. The machine's power has waned considerably since patronage was curtailed with the Shakman Decrees of 1972 and 1983.

The Circuit Court of Cook County, which files more than 1.2 million cases every year,[3] the Cook County Department of Corrections, also known as the Cook County Jail, the largest single-site jail in the nation, and the Cook County Juvenile Detention Center, the first juvenile center in the nation and one of the largest in the nation, are solely the responsibility of Cook County government. The Cook County Law Library is the second largest county law library in the nation.

The Bureau of Health Services administers the county's public health services and is the second largest public health system in the nation. Three hospitals are part of this system: John H. Stroger, Jr. Hospital of Cook County, Provident Hospital, and Oak Forest Hospital of Cook County, along with over 30 clinics.

The Cook County Highway Department is responsible for the design and maintenance of roadways in the county. These thoroughfares are mostly composed of major and minor arterials, with a few local roads. Although the Highway Department was instrumental in designing many of the expressways in the county, today they are under the jurisdiction of the state.

The Forest Preserve District, organized in 1915, is a separate, independent taxing body, but the Cook County Board of Commissioners also acts as the Forest Preserve District Board of Commissioners. The District is a belt of 69,000 acres (275 km²) of forest reservations surrounding the City of Chicago. The Brookfield Zoo (managed by the Chicago Zoological Society) and the Chicago Botanic Garden (managed by the Chicago Horticultural Society) are located in the forest preserves.

In the 1980s, Cook County was ground zero to an extensive FBI investigation named Operation Greylord. Ninety-two officials were indicted, including 17 judges, 48 lawyers, 8 policemen, 10 deputy sheriffs, 8 court officials, and 1 state legislator. Cook County is the fifth largest employer in Chicago.[4]

In March 2008, the Cook County Board increased sales tax one percent, increasing the county sales tax rate from 0.75% to 1.75%. This followed a recent quarter-cent increase in mass transit taxing coming into effect in April. In Chicago, the rate increased to 10.25 percent, the steepest nominal rate of any major metropolitan area in America. In Evanston, sales tax reached 10 percent and Oak Lawn residents will pay 9.5 percent.[5] On July 22, 2008, the Cook County board voted against Cook County Commissioner's proposal to repeal the tax increase.[6]

Presidential Election Results 1960-2008
Year Democrat Republican
2008 76.48% 1,582,973 23.05% 477,038
2004 70.25% 1,439,724 29.15% 597,405
2000 68.63% 1,280,547 28.65% 534,542
1996 66.79% 1,153,289 26.73% 461,557
1992 58.21% 1,249,533 28.20% 605,300
1988 55.77% 1,129,973 43.36% 878,582
1984 51.02% 1,112,641 48.40% 1,055,558
1980 51.99% 1,124,584 39.60% 856,574
1976 53.44% 1,180,814 44.69% 987,498
1972 46.01% 1,063,268 53.41% 1,234,307
1968 50.56% 1,181,316 41.11% 960,493
1964 63.18% 1,537,181 36.82% 895,718
1960 56.37% 1,378,343 43.33% 1,059,607

Secession movements[]

To establish more localized government control and policies which reflect the often different values and needs of large suburban sections of the sprawling county, several secession movements have been made over the years which called for certain townships or municipalities to form their own independent counties.

In the late 1970s, a movement started which proposed a separation of six northwest suburban townships, Cook County's panhandle (Barrington, Hanover, Palatine, Wheeling, Schaumburg, and Elk Grove) from Cook to form Lincoln County, in honor of the former U.S. president and Illinois resident.[7] It is likely that Arlington Heights would have been the county seat. This northwest suburban region of Cook is moderately conservative and has a population over 500,000. Local legislators, led by State Senator Dave Regnar, went so far as to propose it as official legislation in the Illinois House. The legislation died, however, before coming to a vote.

In 2004, Blue Island Mayor Donald E. Peloquin organized a coalition of fifty-five south and southwest suburban municipalities to form a new county, also proposing the name Lincoln County. The county would include everything south of Burbank, stretching as far west as Orland Park, as far east as Calumet City, and as far south as Matteson, covering an expansive area with a population of over one million residents. Peloquin argued that the south suburbs are often shunned by the city and blamed the Chicago-centric policies of Cook County government for failing to jumpstart the long-depressed local economy of the south suburban region. Pending sufficient interest from local communities, Peloquin planned a petition drive to place a question regarding the secession on the general election ballot.[8]

Talk of secession amongst outlying communities again heated up in mid-2008 in response to a highly controversial 1% sales tax hike which has pushed the sales tax rate in Chicago proper to 10.25%, and pushed the nominal tax rates across the various other county communities up amongst the highest in the nation. Border towns in particular have been outraged, as people can take their business across the county border (paying, for instance, 7% in Lake County instead of Palatine's 11%). In March 2009, advisory referenda in Barrington, Hanover and Palatine Townships passed recommending secession from Cook County.


According to the U.S. Census Bureau, the county has a total area of 1,635 square miles (4,234.6 km2), of which 946 square miles (2,450.1 km2) is land and 689 square miles (1,784.5 km2) (42.16%) is water, most of it in Lake Michigan. The highest point in Cook County is its northwest corner, at nearly 1,000 feet above sea level.[9]

Major expressways, US and state routes[]

  • I-55.svg Interstate 55
  • I-57.svg Interstate 57
  • I-80.svg Interstate 80
  • I-88.svg Interstate 88
  • I-90.svg Interstate 90
  • I-94.svg Interstate 94
  • I-190.svg Interstate 190
  • I-290.svg Interstate 290
  • I-294.svg Interstate 294
  • I-355.svg Interstate 355
  • US 6.svg U.S. Highway 6
  • US 12.svg U.S. Highway 12
  • US 14.svg U.S. Highway 14
  • US 20.svg U.S. Highway 20
  • US 30.svg U.S. Highway 30
  • US 34.svg U.S. Highway 34
  • US 41.svg U.S. Highway 41
  • US 45.svg U.S. Highway 45
  • Illinois 1.svg Illinois Route 1
  • Illinois 7.svg Illinois Route 7
  • Illinois 19.svg Illinois Route 19
  • Illinois 21.svg Illinois Route 21
  • Illinois 22.svg Illinois Route 22
  • Illinois 25.svg Illinois Route 25
  • Illinois 38.svg Illinois Route 38
  • Illinois 43.svg Illinois Route 43
  • Illinois 50.svg Illinois Route 50
  • Illinois 53.svg Illinois Route 53
  • Illinois 56.svg Illinois Route 56
  • Illinois 58.svg Illinois Route 58
  • Illinois 59.svg Illinois Route 59
  • Illinois 60.svg Illinois Route 60
  • Illinois 62.svg Illinois Route 62
  • Illinois 64.svg Illinois Route 64
  • Illinois 72.svg Illinois Route 72
  • Illinois 83.svg Illinois Route 83
  • Illinois 68.svg Illinois Route 68
  • Illinois 171.svg Illinois Route 171
  • Illinois 394.svg Illinois Route 394

Adjacent counties[]

National protected area[]

  • Chicago Portage National Historic Site


Historical populations
Census Pop.
1840 10,201
1850 43,385 325.3%
1860 144,954 234.1%
1870 349,966 141.4%
1880 607,524 73.6%
1890 1,191,922 96.2%
1900 1,838,735 54.3%
1910 2,405,233 30.8%
1920 3,053,017 26.9%
1930 3,982,123 30.4%
1940 4,063,342 2.0%
1950 4,508,792 11.0%
1960 5,129,725 13.8%
1970 5,492,369 7.1%
1980 5,253,655 −4.3%
1990 5,105,067 −2.8%
2000 5,376,741 5.3%
2010 5,194,675 −3.4%

2000 census age pyramid for Cook County

Bahá'í House of Worship, Wilmette, Illinois.

As of the 2000 Census,[10] there were 5,376,741 people, 1,974,181 households, and 1,269,398 families residing in the county. The population density was 5,686 people per square mile (2,195/km²). There were 2,096,121 housing units at an average density of 2,216 per square mile (856/km²). The racial makeup of the county was 56.27% White, 26.14% Black or African American, 0.29% Native American, 4.84% Asian, 0.05% Pacific Islander, 9.88% from other races, and 2.53% from two or more races. 19.93% of the population were Hispanic or Latino of any race. 9.1% were of Polish, 8.1% German, 7.9% Irish and 5.7% Italian ancestry according to Census 2000. 17.63% reported speaking Spanish at home; 3.13% speak Polish.[11]

As of the 2010 Census, the population of the county was 5,194,675, White Americans made up 55.4% of Cook County's population; non-Hispanic whites represented 43.9% of the population. Black Americans made up 24.8% of the population. Native Americans made up 0.4% of Cook County's population. Asian Americans made up 6.2% of the population. Pacific Islander Americans made up just 0.0% of the population. Individuals from other races made up 10.6% of the population; people from two or more races made up 2.5% of the county's population. Hispanics and Latinos (of any race) made up 24.0% of Cook County's population.

Whites are the largest racial group in Cook County. Whites of both Hispanic and non-Hispanic origin form a majority (53%) of the population; however, whites of non-Hispanic origin make up just under 45% of the population. This makes Cook County a minority-majority county. Whites (Hispanic and non-Hispanic) number at roughly 2,793,500 individuals. There are roughly 2,372,500 non-Hispanic whites residing in Cook County. The White population is ethnically diverse. The bulk of the White population is of German (11.4%), Irish (10.3%), Polish (9.7%), Italian (6.1%), and English (3.3%) descent. There are sizable numbers of Swedes (1.5%), Russians (1.5%), French (1.3%), Greeks (1.2%), Czechs (1.0%), Dutch (1.0%), Lithuanians (0.9%), Norwegians (0.8%), and Scots (0.8%).

Black Americans are the second largest racial group. Black Americans form over one-quarter (25.4%) of Cook County's population. Blacks of non-Hispanic origin form 25.2% of the population; black Hispanics make up the remaining 0.2% of the populace. There are roughly 1,341,000 African Americans of both Hispanic and non-Hispanic origin living in Cook County; 1,328,000 are non-Hispanic blacks. Roughly 52,500 individuals were of Sub-Saharan African ancestry, making up 1.0% of the total population.

Native Americans are sizable in number but small in the percentage of the population. Over 10,200 residents of Cook County are of Native American heritage, equivalent to just 0.2% of the total population. There are 974 Cherokee, 612 Chippewa, 430 Navajo, and 96 Sioux living in Cook County. Native Americans of Hispanic origin represent much of the Native American population group. Some 5,900 Native Americans are of non-Hispanic origin, so some 4,300 are of Hispanic origin. Over 40% of the Native American racial group is of Hispanic descent.

Asian Americans are a sizable racial group despite the much larger numbers of African and European Americans. Over 300,800 Americans of Asian origin reside in Cook County. Like the Caucasian populace, the Asian population is ethnically diverse, and includes roughly 87,900 Indians, 61,700 Filipinos, 60,700 Chinese, 35,000 Koreans, 13,700 Vietnamese, and 11,100 Japanese. Roughly 30,800 individuals are of other Asian ethnic groups, such as Thai, Cambodian, and Hmong. Indian Americans make up 1.7% of the population, while Chinese and Filipino Americans make up 1.2% of the population each.

Pacific Islander Americans are, by far, the smallest racial group in Cook County. Just over 3,000 individuals are of Pacific Islander heritage. This group includes roughly 780 Native Hawaiians, 670 Guamanians, 120 Samoans, and 1,400 people of other Pacific Islander groups.

Hispanic and Latino Americans make up over one-fifth (22.8%) of Cook County's population. Roughly 1,204,000 Hispanics live in the county. Mexicans are, by far, the most common Hispanic group. Cook County's 925,000 Mexican Americans make up 17.5% of its population. Roughly 127,000 Puerto Ricans make up 2.4% of the population. About 12,200 Cubans form just 0.2% of the total population. There are some 140,000 Hispanics and Latinos of other nationalities living in Cook County (i.e. Colombian, Bolivian, etc., and they collectively make up 2.6% of the county's population.[12][13]

According to the 2000 Census there were 1,974,181 households out of which 30.9% had children under the age of 18 living with them, 44.0% were married couples living together, 15.6% had a female householder with no husband present, and 35.7% were non-families. 29.4% of all households were made up of individuals and 9.3% had someone living alone who was 65 years of age or older. The average household size was 2.68 and the average family size was 3.38.

In the county the population was spread out with 26.0% under the age of 18, 9.9% from 18 to 24, 31.7% from 25 to 44, 20.7% from 45 to 64, and 11.7% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 93.9 males. For every 100 females age 18 and over, there were 90.5 males.

The median income for a household in the county was $45,922, and the median income for a family was $53,784. Males had a median income of $40,690 versus $31,298 for females. The per capita income for the county was $23,227. About 10.6% of families and 13.5% of the population were below the poverty line, including 18.9% of those under age 18 and 10.3% of those age 65 or over.

According to Census Bureau estimates, the county's population was down to 5,303,683 in 2005.[14]


The county is divided into thirty townships, in addition to the City of Chicago.

Worth TownshipWheeling TownshipThornton TownshipStickney TownshipStickney TownshipSchaumburg TownshipRiverside TownshipRiver Forest TownshipRich TownshipProviso TownshipPalos TownshipPalatine TownshipOrland TownshipOak Park TownshipNorwood Park TownshipNorthfield TownshipNiles TownshipNew Trier TownshipMaine TownshipLyons TownshipLeyden TownshipLemont TownshipHanover TownshipEvanston TownshipElk Grove TownshipCicero TownshipCalumet TownshipBremen TownshipBloom TownshipBerwyn TownshipBarrington Township
About this image

Cook County townships (clickable)

Townships by population in 2010[]

  • Thornton Township - 169,326
  • Wheeling Township - 153,630
  • Worth Township - 152,633
  • Proviso Township - 151,704
  • Maine Township - 135,772
  • Schaumburg Township - 131,288
  • Palatine Township - 112,994
  • Lyons Township - 111,688
  • Bremen Township - 110,118
  • Niles Township - 105,882
  • Hanover Township - 99,538
  • Orland Township - 97,558
  • Elk Grove Township - 92,905
  • Leyden Township - 92,890
  • Bloom Township - 90,922
  • Northfield Township - 85,102
  • Cicero Township - 83,891
  • Rich Township - 76,727
  • Evanston Township - 74,486
  • New Trier Township - 55,424
  • Palos Township - 54,615
  • Berwyn Township - 56,657
  • Oak Park Township - 51,878
  • Stickney Township - 40,772
  • Norwood Park Township - 26,385
  • Lemont Township - 21,113
  • Calumet Township - 20,777
  • Barrington Township - 15,636
  • Riverside Township - 15,594
  • River Forest Township - 11,172


Former townships[]

Chicago's eight former townships and annexed parts of others no longer have any governmental structure or responsibility since their annexations, but their names and boundaries are still used on property plats and by Cook County for tax assessment purposes.

  • Jefferson Township
  • Hyde Park Township
  • Lake Township
  • Lake View Township
  • North Township
  • Rogers Park Township
  • South Township
  • West Township


Several municipalities straddle county borders.




  • Franklin Park
  • Glencoe
  • Glenview
  • Glenwood
  • Golf
  • Hanover Park - partly in DuPage County
  • Harwood Heights
  • Hazel Crest
  • Hillside
  • Hinsdale - primarily in DuPage County
  • Hodgkins
  • Hoffman Estates - partly in Kane County
  • Homewood
  • Indian Head Park
  • Inverness
  • Justice
  • Kenilworth
  • La Grange
  • La Grange Park
  • Lansing
  • Lemont
  • Lincolnwood
  • Lynwood
  • Lyons
  • Matteson
  • Maywood
  • McCook
  • Melrose Park
  • Merrionette Park
  • Midlothian
  • Morton Grove

Climate and weather[]

Climate chart for Chicago, Illinois
temperatures in °Cprecipitation totals in mm
source: The Weather Channel[16]

In recent years, average temperatures in Chicago have ranged from a low of 18 °F (−8 °C) in January to a high of 84 °F (29 °C) in July, although a record low of −24 °F (−31.1 °C) was recorded in January 1985 and a record high of 104 °F (40 °C) was recorded in June 1988. Average monthly precipitation ranged from 1.77 inches (45 mm) in February to 4.30 inches (109 mm) in June.[16]

Pop culture references[]

  • NBC medical-drama, ER is set in Cook County. The hospital is named "Cook County General Hospital", although filmed in Los Angeles.
  • The 1928 play The Front Page is a newspaper comedy focused on the impending hanging of a prisoner at the Cook County Jail. The play has been made into at least four movies and four television productions.
  • In the 1980 film, The Blues Brothers, the title characters race to the offices of the Cook County Assessor to pay the back taxes owed by the church-owned orphanage in which the characters were reared. In reality, however, back taxes are paid in the Office of the Cook County Clerk in room 434, and church-owned property is tax exempt anyway. Near the end, a car is driven through the lobby of the Daley Center courthouse, and the County Building is stormed by the title characters and hundreds of policemen and soldiers. Murphy Dunne, who played the pianist in the movie, is the son of then Cook County Board President George Dunne.[17]
  • In the film The Fugitive, a jail visitation is placed not in the jail but in the County Building, again for better visual effect. This film also places the lead character in the old Cook County Hospital for some key scenes.
  • In “Otis”, an episode of the television series Prison Break, LJ Burrows is sent to a court hearing at the Cook County Courthouse, while his father, Lincoln Burrows, and his uncle, Michael Scofield, attempt to take him out of custody by extracting him while he is in the elevator.
  • In 1927's Chicago, 1942's Roxie Hart, and 2002's Chicago (all of which were based upon stage plays entitled Chicago), Roxie Hart is confined to the Cook County Jail.
  • Exterior photography of the Cook County Criminal Courthouse was used frequently on the television series, Hill Street Blues, to set up the program's court scenes.
  • In the 1990 film, Home Alone, the house is located in the inner-ring suburbs of Chicago, in the village of Winnetka which is located around 19 miles (30 km) north of the city in New Trier Township, Cook County.
  • In the sitcom Married with Children, the Bundy family house (as well as the Rhoades/D'Arcy house) is supposed to be in Cook County.
  • In the musical Pal Joey, Ludlow Lowell says that's his real name because "Cook County says it's my name."
  • CBS legal drama The Good Wife is set in Cook County.
  • The lyrics to the song PUT YOUR FAITH IN ME from Dance Dance Revolution 2ndMIX mention Cook county ("Born and raised in Chicago cook county...")


  1. ^ Illinois 2010 Census Results
  2. ^ County Population Estimates
  3. ^ "CIRCUIT COURT OF COOK COUNTY AN INFORMATIONAL GUIDE". 2008. Retrieved 2008-12-16. 
  4. ^ "All the extra cost will be no small change". Chicago Tribune. 2008.,0,2967710.story. Retrieved 2008-03-02. 
  5. ^ "Chicago's Largest Employers". ChicagoBusiness.,0,2967710.story. 
  6. ^ "Cook County Board 'rejects' sales tax increase repeal". Chicago Tribune. 2008-07-22. Retrieved 2008-07-23. 
  7. ^ Cleveland, Charles (September 1977). "Carving another county out of Cook". Illinois Issues. 
  8. ^ "Blue Island mayor wants to create "Lincoln County"". WLS-TV News ( 2004-06-25. 
  9. ^
  10. ^ "American FactFinder". United States Census Bureau. Retrieved 2008-01-31. 
  11. ^
  12. ^
  13. ^
  14. ^ Cook County, Illinois, United States Census Bureau
  15. ^; accessed 2011 May 17
  16. ^ a b "Monthly Averages for Chicago, Illinois". The Weather Channel. Retrieved 2011-01-27. 
  17. ^ "Resolution of the Cook County Board" (PDF). Cook County Clerk. 2006-11-14.  "Biography of Murphy Dunne". Internet Movie Database, 

External links[]

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Coordinates: 41°48′N 87°43′W / 41.8, -87.717

This page uses content from the English language Wikipedia. The original content was at Cook County, Illinois. The list of authors can be seen in the page history. As with this Familypedia wiki, the content of Wikipedia is available under the Creative Commons License.