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Cook County, Illinois



(by Population)




Square Miles
Frank Lloyd Wright Coonley House
Frank Lloyd Wright Coonley House
The Chicago Field Museum
The Chicago Field Museum
The Art Institute of Chicago
The Art Institute of Chicago

The second most populous county in America

Cook County, Illinois is a big county. It’s the second most populous county in the nation after Los Angeles County, California. Including the city of Chicago—the county seat—this expansive county contains 134 municipalities. Unsurprisingly, a big region like that takes a lot of work to manage. The Cook County government ranks as the 19th largest government in the United States.

Chicago also holds a few records for population. It’s the most populous city in the state of Illinois, and it’s the third most populous city in the United States after New York City and Los Angeles. The city of Chicago accounts for a whopping 52% of Cook County’s total population.

Established in 1831

The Native American communities that first called the Cook County region home are the Ojibwa, Ottawa, and Potawatomi. Collectively, these tribes are known as the “Three Fires” due to their shared culture and language. Other tribes that inhabited this area include the Ho-Chunk, Miami, Menominee, Sauk, and Meskwaki.

Cook County was officially founded on January 15, 1831, becoming the 54th county in Illinois at the time. At its founding, the county seat was the Fort Dearborn settlement at the mouth of the Chicago River. That fort and surrounding areas would later transform into the city of Chicago.

Originally, the county had just 100 residents and a land area of 2,464 square miles. As the region became more populated, chunks of Cook County were split off to form Lake, DuPage, and other neighboring counties. In spite of its shrinking land area, Cook County’s population expanded quickly. Just eight years after its founding, the population ballooned to more than 4,000 while the land area diminished to 954 square miles.

The county is named for Daniel Pope Cook. Though he was never known to have traveled to Cook County, he was an important figure in Illinois as the state’s second congressman and first attorney general.

On the shores of Lake Michigan

Cook County is located in northeastern Illinois. On its eastern edge, it borders Lake Michigan and Indiana. To the north, it’s just shy of the border with Wisconsin. Chicago is located in the central portion of the county on the coast of Lake Michigan. The county is mainly characterized by urban areas, but there are also 69,000 acres of natural land, including prairies, woodlands, and waterways.

Cook County encompasses a total area of 1,634 square miles. The land area accounts for 945 square miles, and the water area takes up 689 square miles. The city of Chicago dominates the region, making up about 24% of the county’s land area. As for the water area, most of that comes from Lake Michigan.

Diverse population

As the second most populous county in the country, it’s no surprise that a wide variety of people call Cook County home. It’s the most diverse out of the 99 counties in Illinois, and it’s the tenth most diverse county in the nation.

Cook County has a population of 5,150,233. That number makes up about 40% of the total population of Illinois. It’s a densely populated region with 5,495 people per square mile. Of the residents in Cook County, 65.4% are White, 23.8% are African American, 0.7% are American Indian, 7.9% are Asian, 0.1% are Native Hawaiian or Other Pacific Islander, and 25.6% are Hispanic or Latino. Notably, Chicago is home to the third-largest urban Native American community in the country.

There is also a large immigrant population in the county. Foreign born individuals make up 21.1% of the population, and 35.3% of residents speak a language other than English at home. Both of these numbers are higher than the national averages of 13.6% and 21.6%, respectively. Besides English, the most common languages spoken are Spanish, Polish, and Mandarin and other Chinese dialects.

With several major universities inside its borders, lots of Cook County residents have received a higher education. Those who have received a bachelor’s degree or higher account for 38.8% of the population. That’s comfortably above the national average of 32.1%

The Midwest’s economic center

Cook County is an important economic center for the Midwest and the state of Illinois. It contributes 40% of the total economic activity in the state.

The county is above average in a few other regards. Of working age residents, 66% are part of the labor force. That’s higher than the national average of 63%. The median household income is also above average. In Cook County that number is $64,660, while the national average is $62,843.

The largest industries in Cook County are healthcare/social assistance, professional scientific/technical services, and manufacturing. The most common jobs are office/administrative support, sales, and management.

Government is a particularly large employer in the area. The federal, state, county, and city of Chicago governments are all among the top employers. Education is another large employer, including Chicago Public Schools, University of Chicago, and Northwestern University. Finally, there are several major employers in the healthcare sector, like Northwestern Memorial Healthcare, Advocate Aurora Health, and Amita Health.

Explore the windy city

As one of the biggest cities in the country, there’s no shortage of fun things to do in Chicago.

The Art Institute of Chicago is a world-renowned art museum that is not to be missed. Located in the heart of downtown Chicago, it’s one of the oldest and largest art museums in the United States. The spectacular stained-glass windows created specifically for the museum by French artist Marc Chagall are a must-see exhibit.

For some natural history, explore the Field Museum. Since 1894, this museum has been showing off amazing fossils and artifacts. Today, they maintain a collection of almost 40 million specimens. If you’d rather get up close with some living specimens, schedule a visit to the Shedd Aquarium. They have amazing exhibits with an array of wildlife, including penguins, stingrays, giant octopus, and much more.

Does it count as a visit to Chicago if you don’t take a photo in front of the iconic Bean? Stroll through Millennium Park for your required photo op and admire the Lurie Garden and Crown Fountain while you’re at it.

Chicago is home to a thriving performing arts scene. You can catch world-class musicals and plays in the downtown Theatre District or see a more intimate show at one of the many independent theatres. If you’re a comedy fan, a visit to the legendary Second City—where Tina Fey, Bill Murray, and so many others got their start—is required.

While you could spend a whole weekend in Chicago and not even scratch the surface of what the city has to offer, the rest of the county is worth exploring too.

Just north of Chicago, Evanston boasts several unique museums like the Block Museum of Art at Northwestern, the Mitchell Museum of the American Indian, and the Halim Time and Glass Museum. In Skokie, you can bike or walk along the 2-mile Northshore Sculpture Park or take a kayak out on the Skokie Lagoons. Just north of Skokie, you’ll find the sprawling Chicago Botanic Gardens in Glencoe. In Brookfield, check out the animals at the Brookfield Zoo and then head over to neighboring Riverside to admire the historic Coonley House designed by Frank Lloyd Wright. Finally, you can get lost exploring the 3,558 acres of Busse Woods. Go for a hike, take a boat out on Busse Lake, or visit the thriving Elk habitat.

Additional Cook County Information