Chicago at a Glance: Key Facts About the Windy City

Chicago is the third-largest city in the United States, with 2,746,388 residents in the 2020 Census and an estimated 2,731,585 as of July 1, 2025. It sits on the southwest shore of Lake Michigan in Cook County, Illinois, and was incorporated as a city on March 4, 1837. Its best-known nicknames are the Windy City, the Second City, Chi-Town and the City of Big Shoulders.

Fact	Detail
Population (2020 Census)	2,746,388
Population (July 1, 2025 estimate)	2,731,585
Rank among U.S. cities	3rd, after New York and Los Angeles
Land area	About 227.7 square miles (about 234.5 square miles including water)
State and county	Illinois; Cook County (a small part of O’Hare Airport extends into DuPage County)
Incorporated as a town	August 12, 1833
Incorporated as a city	March 4, 1837
First mayor	William B. Ogden (1837–1838)
Current mayor	Brandon Johnson, inaugurated May 15, 2023
Community areas	77
City Council wards	50
Time zone	Central Time (CST, UTC−6; CDT, UTC−5 in daylight saving time)
Area codes	312, 773 and 872
Motto	Urbs in Horto (“City in a Garden”)

Where Chicago is

Chicago lies in northeastern Illinois on the southwest shore of Lake Michigan, one of the five Great Lakes. The city has about 28 miles of lakefront and 24 beaches, according to Choose Chicago. The Chicago River runs through downtown and connects the lake to the Mississippi River system by canal.

Almost all of the city is in Cook County, which is also the county seat. A small part of O’Hare International Airport, on the city’s far northwest edge, is in DuPage County. For a deeper look at the lake, river, street grid and the city’s sides, see Chicago geography and layout.

Population and size

The 2020 Census counted 2,746,388 people in Chicago, an increase of 50,790 residents, or about 1.9%, from 2010. The Census Bureau’s most recent estimate puts the population at 2,731,585 as of July 1, 2025. Chicago remains the third-most-populous U.S. city, behind New York City and Los Angeles.

Census figures give Chicago about 227.7 square miles of land and about 6.8 square miles of water, for a total near 234.5 square miles. The city is divided into 77 official community areas, which are the standard units for neighborhood statistics. See Chicago’s 77 community areas for the full list.

Founding and incorporation

Jean Baptiste Point du Sable, a Black man of Haitian origin, is recognized as Chicago’s first permanent non-Indigenous settler; he arrived at the mouth of the Chicago River in the 1770s. Choose Chicago dates his settlement to 1779. The U.S. government built Fort Dearborn near the river mouth in 1803.

Chicago was incorporated as a town on August 12, 1833, and as a city on March 4, 1837. The city had about 4,000 residents at incorporation. William B. Ogden served as the first mayor, from 1837 to 1838. Chicago marks its birthday each year on March 4. The full timeline is on our Chicago history page.

The name was first recorded in 1688 as “Chigagou,” an Algonquian word that Choose Chicago translates as “onion field.”

Chicago’s nicknames and where they came from

Nickname	Origin
The Windy City	The Cincinnati Enquirer used it in an 1876 headline about a tornado in Chicago. A popular story credits a New York editor mocking Chicago’s 1893 World’s Fair bid, but the nickname is older than that jab. Historians suspect it has always had a double meaning: the weather and boastful local talk.
The Second City	Chicago was the second-most-populous U.S. city for nearly a century, which is the likeliest source. New Yorker writer A.J. Liebling popularized the phrase with his essays collected as Chicago: The Second City. A less likely theory ties it to the city rebuilt after the 1871 fire.
City of Big Shoulders	From Carl Sandburg’s 1914 poem “Chicago,” which pictures the city as a tough, hard-working young laborer.
Chi-Town / Chi	A shortened, informal form of the city’s name.
The White City	The name given to the white neoclassical buildings of the 1893 World’s Columbian Exposition.
The City That Works	One of the nicknames listed by Choose Chicago.

Chicago is not especially windy by the numbers. WTTW reports that it ranks only about 12th among U.S. cities for wind. Read more in our Chicago weather guide.

The Chicago flag

Chicago’s flag was designed by Wallace Rice, who won a City Council design contest in 1917. It has two blue horizontal stripes on a white field, with four six-pointed stars across the middle. The stars have six points because five-pointed stars are used for sovereign states.

Element	What it stands for
Top blue stripe	Lake Michigan and the North Branch of the Chicago River
Bottom blue stripe	The South Branch of the river and the canal linking it to the Des Plaines River
Three white bands	The North, West and South sides of the city
Fort Dearborn star (added 1939)	The founding of Fort Dearborn
Great Chicago Fire star (1917)	The fire of 1871
World’s Columbian Exposition star (1917)	The 1893 world’s fair
Century of Progress star (added 1933)	The 1933–34 world’s fair

Each star’s six points carry their own meanings. The fire star’s points stand for transportation, labor, commerce, finance, populousness and health. The 1893 fair star’s points stand for religion, education, aesthetics, justice, benevolence and civic spirit.

Motto: Urbs in Horto

Chicago’s official motto is Urbs in Horto, Latin for “City in a Garden.” Choose Chicago dates its adoption to the 1830s, the decade the city was incorporated. The city has more than 600 parks and more than 8,800 acres of green space, and the Chicago Park District is the largest municipal park manager in the nation.

Chicago by the numbers

Measure	Number	Source
Lakefront	28 miles	Choose Chicago
Beaches	24	Choose Chicago
Parks	600+	Choose Chicago
Museums	60+	Choose Chicago
Theaters	200+	Choose Chicago
Major league sports teams	8	Choose Chicago
CTA rides in an average year	450 million+	Choose Chicago
Downtown hotels	135 hotels, 43,881 rooms	Choose Chicago
Metro economy (2024)	About $927 billion gross regional product	Chicago Business Climate Snapshot, Jan. 2026
Fortune 500 headquarters (metro, 2026)	30, second in the U.S.	Chicago Business Climate Snapshot, Jan. 2026

For jobs, industries and headquarters, see Chicago’s economy. For how the city is run, see Chicago government.

Frequently asked questions

What is the population of Chicago?

The 2020 Census counted 2,746,388 people in Chicago. The Census Bureau estimated 2,731,585 residents as of July 1, 2025.

Is Chicago the second-largest city in the U.S.?

No. Chicago is the third-largest U.S. city, after New York and Los Angeles. It was second for much of its history, which is one source of the “Second City” nickname.

What county is Chicago in?

Chicago is in Cook County, Illinois, and is the county seat. A small part of O’Hare Airport lies in DuPage County.

When was Chicago founded?

Chicago was incorporated as a town on August 12, 1833, and as a city on March 4, 1837. Jean Baptiste Point du Sable settled at the river mouth in the 1770s.

What time zone is Chicago in?

Chicago uses Central Time: UTC−6 in standard time and UTC−5 during daylight saving time.

What do the four stars on the Chicago flag mean?

They stand for Fort Dearborn, the Great Chicago Fire of 1871, the 1893 World’s Columbian Exposition and the 1933–34 Century of Progress fair.

Related guides

Sources

Last updated: October 31, 2026