Cook County sits on Lake Michigan in northeastern Illinois. Chicago is the county seat. The 2020 population was 5,275,541, the second-highest of any US county and more than 28 individual states. The county covers 1,635 square miles, nearly half of that water. In 1831 it had 600 residents; a century later, 4 million, growth that rivaled Paris over the same period. Today there are 134 municipalities and over 800 separate local government units within its borders. The Art Institute of Chicago and Millennium Park are both here. Cicero, just west of Chicago, is the county's most densely packed municipality.
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Cook County administration contact details
| County seat | Chicago |
|---|---|
| Phone number | (312) 603-5500 |
| Official website | https://www.cookcountyil.gov/ |
| County clerk | Karen A. Yarbrough |
| County auditor | Sean T. Morrison |
| County fiscal officer | Lawrence Wilson |
| County permits office or building department contact details | (312) 603-0500 |
| County commissioner | Toni Preckwinkle |
Cook County Sheriff's Office and Jail Information
| Number of prisons | 1 |
|---|---|
| Jail names | Cook County Jail |
| Sheriff office address | 50 W. Washington Street, Room 704, Chicago, IL 60602 |
| Sheriff office phone number | 312-603-6444 |
| Inmate search information | To locate an inmate in Cook County, you can use the Inmate Locator tool on the Cook County Sheriff's website or call the Sheriff's office for assistance. |
| Clerk of Court name | Iris Y. Martinez |
| Clerk of Court address | 50 W. Washington Street, Room 1001, Chicago, IL 60602 |
Cook County Statistics
| Number of cities/towns/villages | 134 |
|---|---|
| Population | 5248523 |
| Area | 945 sq mi |
| Density | 5553 /sq mi |
| Altitude | 594 ft |
| GDP | $362 billion |
| Median Household Income | $68658 |
| Poverty rate | 14% |
| Unemployment rate | 7% |
| Educational Attainment | 38% Bachelor's Degree or higher |
| Crime rate | 3150 per 100,000 people |
Environmental risk in Cook County, IL
| Overall risk | Very High |
|---|---|
| Expected Annual Loss | Very High |
| Social Vulnerability | Very High |
| Community Resilience | Relatively High |
| Avalanche Risk | Not Applicable |
| Coastal Flooding Risk | Very Low |
| Cold Wave Risk | Very High |
| Drought Risk | Very Low |
| Earthquake Risk | Relatively Moderate |
List of cities and towns in Illinois County by population size
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