Cook County is a county in the U.S. state of Illinois. It is the second-most populous county in the United States after Los Angeles County, California. As of 2017, the population was 5,211,263. Its county seat is Chicago, the most populous city in Illinois and the third-most populous city in the United States. More than 40% of all residents of Illinois live in Cook County.
According to the U.S. Census Bureau, the county has a total area of 1,635 square miles (4,230 km), of which 945 square miles (2,450 km) is land and 690 square miles (1,800 km) (42.2%) is water. It is the sixth largest county in Illinois by land area, and the largest in total area. Most of the water is in Lake Michigan. The highest point is more than 950 feet (290 m), and is in northwest Barrington Township, in the northwest corner of the county. The lowest point is less than 580 feet (180 m), along the Lake Michigan shoreline.
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. African 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 (1.8% Indian, 1.2% Filipino, 1.2% Chinese, 0.7% Korean, 0.3% Vietnamese, 0.2% Japanese, 0.8% Other). Pacific Islander Americans made up less than 0.1% of the population. People 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.
As of the 2000 Census, 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 Islanders, 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. 17.63% reported speaking Spanish at home; 3.13% speak Polish.
Whites (Hispanic and non-Hispanic) number roughly 2,793,500. There are about 2,372,500 non-Hispanic whites residing in Cook County. Sizeable non-Hispanic white populations are those of German (11.4%), Irish (10.3%), Polish (9.7%), Italian (6.1%), and British (4.1%) descent. There are also significant groups of Swedish (1.5%), Russian (1.5%), French (1.3%), Greek (1.2%), Czech (1.0%), Dutch (1.0%), Lithuanian (0.9%), and Norwegian (0.8%) descent.
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 people were of Sub-Saharan African ancestry, making up 1.0% of the total population.
The Native American population is sizeable but small proportionally. Over 10,200 residents of Cook County are of Native American ancestry, 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 sizeable racial group in the county, numbering over 300,800. 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 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 form the smallest racial group in Cook County. Just over 3,000 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 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.
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 someone living alone including 9.3% who were 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 age distribution was: 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 5,211,263 in 2017, decreased further by 2010 (5,194,675) and had grown slightly by 2017 (5,211,263).