Selecting a Suitable Concrete Mix for Piers

Country United StatesStates Illinois
Indiana
WisconsinCore city ChicagoSatellite cities

Area

 • Metro

10,856 sq mi (28,120 km²)Highest elevation

673 ft (205 m)Lowest elevation

579 ft (176 m)Population

 • Density886/sq mi (342/km²) • Metropolitan Statistical Area (MSA) (2022)

9,441,957^[2] (3rd) • Combined Statistical Area (CSA) (2022)

9,806,184 ^[3] (4th)DemonymChicagolanderGDP

 • Metropolitan Statistical Area (MSA)$894.862 billion (2023) • Combined Statistical Area (CSA)$919.229 billion (2023)Time zoneUTC−6 (CST) • Summer (DST)UTC−5 (CDT)Area codes219, 224/847, 262, 312/872, 331/630, 574, 464/708, 773/872 and 779/815

The Chicago metropolitan area, also referred to as Chicagoland, is the largest metropolitan statistical area in the U.S. state of Illinois, and the Midwest, containing the City of Chicago along with its surrounding suburbs and satellite cities. Encompassing 10,286 square mi (28,120 km²), the metropolitan area includes the city of Chicago, its suburbs and hinterland, that span 13 counties across northeast Illinois and northwest Indiana. The MSA had a 2020 census population of 9,618,502 and the combined statistical area, which spans 19 counties and additionally extends into southeast Wisconsin, had a population of nearly 10 million people.^[5][6] The Chicago area is the third-largest metropolitan area in the United States and the fourth-largest metropolitan area in North America (after Mexico City, New York City, and Los Angeles), and the largest in the Great Lakes megalopolis. Its urban area is one of the 40 largest in the world.

According to the 2020 census, the metropolitan's population is approaching the 10 million mark. The metropolitan area has seen a substantial increase of Latin American residents on top of its already large Latino population, and the Asian American population also increased according to the 2020 Census. The metro area has a large number of White, Black, Latino, Asian, and Arab American residents, and also has Native American residents in the region, making the Chicago metropolitan area population truly diverse. The Chicago metropolitan area represents about 3 percent of the entire US population.

Chicagoland has one of the world's largest and most diversified economies. With more than six million full and part-time employees, the Chicago metropolitan area is a key factor of the Illinois economy, as the state has an annual GDP of over $1 trillion.^[7] The Chicago metropolitan area generated an annual gross regional product (GRP) of approximately $700 billion in 2018.^[8] The region is home to more than 400 major corporate headquarters, including 31 in the Fortune 500^[9] such as McDonald's, United, and Blue Cross Blue Shield. With many companies moving to Chicagoland, and many current companies expanding, the area ranked as the nation's top metropolitan area for corporation relocations and expansions for nine consecutive years, the most consecutive years for any region in the country.^[10]

The Chicago area is home to a number of the nation's leading research universities including the University of Chicago, Northwestern University, the University of Illinois at Chicago, DePaul University, Loyola University, and the Illinois Institute of Technology (IIT). The University of Chicago and Northwestern University are consistently ranked as two of the best universities in the world.

There are many transportation options around the region. Chicagoland has three separate rail networks; the Chicago Transit Authority (CTA), Metra, and the South Shore Line. The CTA operates elevated and subway lines that run primarily throughout the city, Downtown Chicago, and into some suburbs. The CTA operates some of its rail lines 24 hours a day, every day of the year, nonstop service, making Chicago, New York City, and Copenhagen the only three cities in the world to offer some 24 hour rail service running nonstop, everyday throughout their city limits. The Metra commuter rail network runs numerous lines between Downtown Chicago and suburban/satellite cities, with one line stretching to Kenosha, Wisconsin, which is part of the Chicago metropolitan area. The interurban South Shore Line runs between Downtown Chicago and the northwest Indiana portion of the metropolitan area. In addition, Amtrak operates Union Station in Downtown Chicago as one of its largest rail hubs, with numerous lines radiating to and from the station.

CTA bus routes serve the city proper, with some service into the suburbs. Pace bus routes serve the suburbs, with some service into the city. In addition, numerous CTA bus routes operate 24 hours a day, nonstop.

The Chicago metropolitan statistical area (MSA) was originally designated by the United States Census Bureau in 1950. It comprised the Illinois counties of Cook, DuPage, Kane, Lake and Will, along with Lake County in Indiana. As surrounding counties saw an increase in their population densities and the number of their residents employed within Cook County, they met Census criteria to be added to the MSA. The Chicago MSA, now defined by the U.S. Office of Management and Budget (OMB) as the Chicago–Naperville–Elgin, IL–IN–WI Metropolitan Statistical Area, is the third-largest MSA by population in the United States. The 2022 census estimate for the population of the MSA was 9,441,957.^[11]

The Chicago MSA is further subdivided into four metropolitan divisions. A breakdown of the county constituents and 2021 estimated populations of the four metropolitan divisions of the MSA are as follows:^[11]

The OMB also defines a slightly larger region as a combined statistical area (CSA). The Chicago–Naperville, IL–IN–WI Combined Statistical Area combines the following core-based statistical areas, listed with their 2021 estimated populations. The combined statistical area as a whole had a population of 9,806,184 as of 2022.^[11]

• Chicago–Naperville–Elgin, IL–IN–WI metropolitan statistical area (9,509,934)
• Kankakee, IL metropolitan statistical area (106,601)
  • Kankakee County, Illinois (106,601)
• Michigan City–La Porte, IN metropolitan statistical area (112,390)
  • LaPorte County, Indiana (112,390)
• Ottawa, IL micropolitan statistical area (147,414)
  • Bureau County, Illinois (32,883)
  • LaSalle County, Illinois (108,965)
  • Putnam County, Illinois (5,566)

The Chicago urban agglomeration, according to the United Nations World Urbanization Prospects report (2023 revision), lists a population of 8,937,000.^[12] The term "urban agglomeration" refers to the population contained within the contours of a contiguous territory inhabited at urban density levels. It usually incorporates the population in a city, plus that in the contiguous urban, or built-up area.

Chicagoland is an informal name for the Chicago metropolitan area. The term Chicagoland has no official definition, and the region is often considered to include areas beyond the corresponding MSA, as well as portions of the greater CSA.^{[citation needed]}

Colonel Robert R. McCormick, editor and publisher of the Chicago Tribune, usually gets credit for placing the term in common use.^[14][15] McCormick's conception of Chicagoland stretched all the way to nearby parts of four states (Indiana, Wisconsin, Michigan, and Iowa).^[14] The first usage was in the Tribune's July 27, 1926, front page headline, "Chicagoland's Shrines: A Tour of Discoveries", for an article by reporter James O'Donnell Bennett.^[16] He stated that Chicagoland comprised everything in a 200-mile (320 km) radius in every direction and reported on many different places in the area. The Tribune was the dominant newspaper in a vast area stretching to the west of the city, and that hinterland was closely tied to the metropolis by rail lines and commercial links.^[17]

Today, the Chicago Tribune's usage includes the city of Chicago, the rest of Cook County, eight nearby Illinois counties (Lake, McHenry, DuPage, Kane, Kendall, Grundy, Will, and Kankakee), and the two Indiana counties of Lake and Porter.^[18] Illinois Department of Tourism literature uses Chicagoland for suburbs in Cook, Lake, DuPage, Kane, and Will counties,^[19] treating the city separately. The Chicagoland Chamber of Commerce defines it as all of Cook, DuPage, Kane, Lake, McHenry, and Will counties.^[20]

In addition, company marketing programs such as Construction Data Company's^[21] "Chicago and Vicinity" region and the Chicago Automobile Trade Association's "Chicagoland and Northwest Indiana" advertising campaign are directed at the MSA itself, as well as LaSalle, Winnebago (Rockford), Boone, and Ogle counties in Illinois, in addition to Jasper, Newton, and La Porte counties in Indiana and Kenosha, Racine, and Walworth counties in Wisconsin, and even as far northeast as Berrien County, Michigan. The region is part of the Great Lakes Megalopolis, containing an estimated 54 million people.^{[citation needed]}

The term "collar counties" is a colloquialism for the five counties (DuPage, Kane, Lake, McHenry, and Will) of Illinois that border Chicago's Cook County. After Cook County, they are also the next five most populous counties in the state. According to the Encyclopedia of Chicago, there is no specifically known origin of the phrase, but it has been commonly used among policy makers, urban planners, and in the media. However, it also notes that as growth has spread beyond these counties, it may have lost some of its usefulness.^[22]

Chicago Metropolitan Agency for Planning (CMAP) is an Illinois state agency responsible for transportation infrastructure, land use, and long-term economic development planning for the areas under its jurisdiction within Illinois.^[23] The planning area has a population of over 8 million, which includes the following locations in Illinois:^[24]

The city of Chicago lies in the Chicago Plain, a flat and broad area characterized by little topographical relief. The few low hills are sand ridges. North of the Chicago Plain, steep bluffs and ravines run alongside Lake Michigan.

Along the southern shore of the Chicago Plain, sand dunes run alongside the lake. The tallest dunes reach up to near 200 feet (61 m) and are found in Indiana Dunes National Park. Surrounding the low plain are bands of moraines in the south and west suburbs. These areas are higher and hillier than the Chicago Plain. A continental divide, separating the Mississippi River watershed from that of the Great Lakes and Saint Lawrence River, runs through the Chicago area.

A 2012 survey of the urban trees and forests in the seven county Illinois section of the Chicago area found that 21% of the land is covered by the tree and shrub canopy, made up of about 157,142,000 trees. The five most common tree species are buckthorn, green ash, boxelder, black cherry, and American elm. These resources perform important functions in carbon storage, water recycling, and energy saving.^[25][26]

As of 2022, the metropolitan area had a population of 9,442,159. The population density was 1,312.3 per square mile. The racial makeup was 50.1% Non-Hispanic White, 23.4% were Hispanic, 15.5% were Non-Hispanic African Americans, 7.2% were Asian, 0.1% were Non-Hispanic Native American, 0.4% identified as “some other race,” and 3.2% were non-Hispanic multiracial.^[27]

According to 2022 estimates from the American Community Survey, the largest ancestries in the Chicago metro area were Mexican (18%), African (17.7%), German (12.8%), Irish (9.9%), Polish (8%), Italian (5.9%), English (5.2%), Indian (2.7%), Puerto Rican (2.3%), Filipino (1.7%), Swedish (1.5%), and Chinese (1.4%).^{[28][29][30][31]}

The suburbs, surrounded by easily annexed flat ground, have been expanding at a tremendous rate since the early 1960s. Aurora, Elgin, Joliet, and Naperville are noteworthy for being four of the few boomburbs outside the Sun Belt, West Coast and Mountain States regions, and exurban Kendall County ranked as the fastest-growing county (among counties with a population greater than 10,000) in the United States between the years 2000 and 2007.^[32]

Settlement patterns in the Chicago metropolitan area tend to follow those in the city proper: the northern and northwestern suburbs are generally affluent and upper-middle class, while the southern suburbs (sometimes known as Chicago Southland) have somewhat lower median incomes and a cost of living, with the exception being the southwest suburbs which contain many upper-middle class areas. Another exception to this is the West Side, which has a somewhat lower median income, but the western suburbs contain many affluent and upper-middle class areas. According to the 2000 Census, DuPage County as a whole had the highest median household income of any county in the Midwestern United States, although there are individual cities and towns in other surrounding counties in the metro that have even higher median incomes.

According to 2022 estimates from the U.S. Census, poverty rates of the largest counties from least poverty to most are as follows: McHenry 4.0%, Dupage 6.7%, Will 6.9%, Kane 7.8%, Lake 8.0%, and Cook 13.6%.^[33] However, Cook County, which contains luxury high rises and expensive houses in sections of the city and expensive houses along the waterfront in the North Shore area, would also have the highest percentage of expensive homes in the region.

In an in-depth historical analysis, Keating (2004, 2005) examined the origins of 233 settlements that by 1900 had become suburbs or city neighborhoods of the Chicago metropolitan area. The settlements began as farm centers (41%), industrial towns (30%), residential railroad suburbs (15%), and recreational/institutional centers (13%). Although relations between the different settlement types were at times contentious, there also was cooperation in such undertakings as the construction of high schools.^{[citation needed]}

As the Chicago metropolitan area has grown, more counties have been partly or totally assimilated with the taking of each decennial census.

Census Area	Area Type	2020 census	2010 census	2000 census	1990 census	1980 Census	1970 census	1960 census	1950 census
Chicago-Naperville-Joliet, IL-IN-WI	Metropolitan	9,618,502	9,461,105	9,098,316	8,065,633	7,869,542	7,612,314	6,794,461	5,495,364
Cook County, Illinois	Metropolitan	5,275,541	5,194,675	5,376,741	5,105,067	5,253,655	5,492,369	5,129,725	4,508,792
DeKalb County, Illinois	Metropolitan	100,420	105,160	88,969	77,932	74,624	71,654	51,714	40,781
DuPage County, Illinois	Metropolitan	932,877	916,924	904,161	781,666	658,835	491,882	313,459	154,599
Grundy County, Illinois	Metropolitan	52,533	50,063	37,535	32,337	30,582	26,535	22,350	19,217
Kane County, Illinois	Metropolitan	516,522	515,269	404,119	317,471	278,405	251,005	208,246	150,388
Kendall County, Illinois	Metropolitan	131,869	114,736	54,544	39,413	37,202	26,374	17,540	12,115
McHenry County, Illinois	Metropolitan	310,229	308,760	260,077	183,241	147,897	111,555	84,210	50,656
Will County, Illinois	Metropolitan	696,355	677,560	502,266	357,313	324,460	249,498	191,617	134,336
Jasper County, Indiana	Metropolitan	32,918	33,478	30,043	24,960	26,138	20,429	18,842	17,031
Lake County, Indiana	Metropolitan	498,700	496,005	484,564	475,594	522,965	546,253	513,269	368,152
Newton County, Indiana	Metropolitan	13,830	14,244	14,566	13,551	14,844	11,606	11,502	11,006
Porter County, Indiana	Metropolitan	173,215	164,343	146,798	128,932	119,816	87,114	60,279	40,076
Lake County, Illinois	Metropolitan	714,342	703,462	644,356	516,418	440,372	382,638	293,656	179,097
Kenosha County, Wisconsin	Metropolitan	169,151	166,426	149,577	128,181	123,137	117,917	100,615	75,238
Kankakee County, Illinois	Combined	107,502	113,449	103,833	96,255	102,926	97,250	92,063	73,524
LaSalle County, Illinois	Combined	109,658	113,924	111,509	106,913	112,003	111,409	110,800	100,610
Bureau County, Illinois	Combined	33,244	34,978	35,503	35,688	39,114	38,541	37,594	37,711
Putnam County, Illinois	Combined	5,637	6,006	6,086	5,730	6,085	5,007	4,570	4,746
LaPorte County, Indiana	Combined	112,417	111,467	110,106	107,066	108,632	105,342	95,111	76,808
Chicago-Naperville-Joliet, IL-IN-WI	Combined	9,986,960	9,686,021	9,312,255	8,385,397	8,264,490	8,089,421	7,204,198	5,911,816

Counties highlighted in gray were not included in the MSA for that census. The CSA totals in blue are the totals of all the counties listed above, regardless of whether they were included in the Chicago Combined Statistical Area at the time.^[34]

• Chicago (2,746,388)

• Aurora, Illinois (180,542)
• Joliet, Illinois (150,362)
• Naperville, Illinois (149,540)
• Elgin, Illinois (114,797)

Within the boundary of the 16-county Chicago Combined Statistical Area lies the Chicago urban area, as well as 26 smaller urban areas.^[35] Some of the urban areas below may partially cross into other statistical areas. Only those situated primarily within the Chicago combined statistical area are listed here.

Urban area	Population (2020 census)	Land area (sq mi)	Land area (km2)	Density (population / sq mi)	Density (population / km2)
Chicago, IL–IN	8,671,746	2,337.89	6,055.09	3,709.2	1,432.1
Round Lake Beach–McHenry–Grayslake, IL–WI	261,835	127.61	330.52	2,051.8	792.2
Kenosha, WI	125,865	56.17	145.48	2,240.8	865.2
Michigan City–La Porte, IN–MI	71,367	49.16	127.32	1,451.7	560.5
Kankakee, IL	66,530	31.66	82.00	2,101.4	811.3
DeKalb, IL	64,736	25.63	66.39	2,525.6	975.1
Valparaiso–Shorewood Forest, IN	51,867	33.64	87.12	1,542.0	595.4
Peru–LaSalle, IL	29,763	21.45	55.56	1,387.4	535.7
Woodstock, IL	25,298	9.31	24.10	2,718.7	1,049.7
Ottawa, IL	20,122	9.99	25.87	2,014.2	777.7
Streator, IL	16,209	8.12	21.04	1,995.3	770.4
Coal City–Braidwood, IL	15,837	10.29	26.65	1,539.4	594.4
Morris, IL	15,740	8.64	22.37	1,822.2	703.5
Lowell, IN	10,747	5.28	13.66	2,037.2	786.6
Manteno, IL	10,437	6.01	15.56	1,736.8	670.6
Harvard, IL	9,376	4.36	11.30	2,148.7	829.6
Princeton, IL	7,979	6.20	16.06	1,287.1	497.0
Marengo, IL	7,509	3.81	9.86	1,971.5	761.2
Lake Holiday, IL	7,313	4.30	11.14	1,700.5	656.6
Mendota, IL	6,918	2.85	7.38	2,426.2	936.8
Wilmington, IL	6,388	3.95	10.23	1,617.3	624.5
McHenry Northwest–Wonder Lake, IL	5,758	2.35	6.08	2,453.6	947.4
Hampshire, IL	5,699	2.72	7.06	2,091.4	807.5
Rensselaer, IN	5,509	3.23	8.37	1,703.9	657.9
Genoa, IL	5,484	2.20	5.69	2,498.0	964.5
Westville, IN	5,189	2.10	5.45	2,466.0	952.1
Marseilles, IL	4,660	2.39	6.19	1,948.4	752.3

The Chicago metropolitan area is home to the corporate headquarters of 57 Fortune 1000 companies, including AbbVie Inc., Allstate, Kraft Heinz, McDonald's, Mondelez International, Motorola, United Airlines, Walgreens, and more. The Chicago area also headquarters a wide variety of global financial institutions including Citadel LLC, Discover Financial Services, Morningstar, Inc., CNA Financial, and more. Chicago is home to the largest futures exchange in the world, the Chicago Mercantile Exchange. In March 2008, the Chicago Mercantile Exchange announced its acquisition of NYMEX Holdings Inc, the parent company of the New York Mercantile Exchange and Commodity Exchange. CME'S acquisition of NYMEX was completed in August 2008.

A key piece of infrastructure for several generations was the Union Stock Yards of Chicago, which from 1865 until 1971 penned and slaughtered millions of cattle and hogs into standardized cuts of beef and pork. This prompted poet Carl Sandburg to describe Chicago as the "Hog Butcher for the World".^[36]

The Chicago area, meanwhile, began to produce significant quantities of telecommunications gear, electronics, steel, crude oil derivatives, automobiles, and industrial capital goods.

By the early 2000s, Illinois' economy had moved toward a dependence on high-value-added services, such as financial trading, higher education, logistics, and health care. In some cases, these services clustered around institutions that hearkened back to Illinois's earlier economies. For example, the Chicago Mercantile Exchange, a trading exchange for global derivatives, had begun its life as an agricultural futures market.

In 2007, the area ranked first among U.S. metro areas in the number of new and expanded corporate facilities.^[37] It ranked third in 2008, behind the Houston–Sugar Land–Baytown and Dallas–Fort Worth metropolitan areas,^[38] and ranked second behind the New York metropolitan area in 2009.^[39]

The Wall Street Journal summarized the Chicago area's economy in November 2006 with the comment that "Chicago has survived by repeatedly reinventing itself."^[40]

• Chicago O'Hare International Airport (ORD)
• Chicago Midway International Airport (MDW)
• Milwaukee Mitchell International Airport (MKE) (located in the adjacent Milwaukee metropolitan area)
• Chicago Rockford International Airport (RFD) (located in the adjacent Rockford metropolitan area)
• Gary/Chicago International Airport (GYY)

• Port of Chicago
• Port of Indiana-Burns Harbor

Chicago has been at the center of the United States' railroad network since the 19th century. Almost all Class I railroads serve the area, the most in North America.^[41]

• Chicago Transit Authority trains, locally referred to as "the 'L' ", (after "elevated train") serving Chicago and the near suburbs
• Pace Suburban Bus operates suburban bus and regional vanpool, paratransit, and ride-matching services in the Chicagoland region.
• Metra run by the Northeast Illinois Regional Commuter Railroad Corporation:
  • 4 lines serving southern Cook County and Will County
  • 3 lines serving western Cook County, DuPage County, and Kane County
  • 2 lines serving northern Cook County and Lake County
  • 1 line serving northern Cook County, Lake County, and Kenosha County
  • 1 line serving northwestern Cook County and McHenry County
• South Shore Line shares the Metra Electric Line in Illinois and connects Chicago to Gary, Michigan City, and ending at South Bend.
• Amtrak operates Union Station which is the major Amtrak passenger rail hub with connections to Metra and the within a few blocks of connections to several 'L' lines. Amtrak also operates a connecting station out of Joliet.

• Interstate 41 (I-41) runs concurrently with Interstate 94 from the northern terminus of the Tri-State Tollway to Milwaukee.
• Interstate 55 (I-55) is the Adlai Stevenson Expy.
• I-355 is the Veterans Memorial Tollway (formerly North-South Tollway).
• I-57 is unofficially the "West Leg" of the Dan Ryan Expy.
• I-65 has no name, whether official or unofficial.
• I-80 is officially called the Borman Expy (cosigned with I-94), Kingery Expy (cosigned with I-94 for 3 miles), Tri-State Tollway (cosigned with I-294 for 4 miles) and is unofficially called the Moline Expy west of I-294.
• I-88 is the Ronald Reagan Memorial Tollway (formerly East-West Tollway)
• I-90 is locally known as Jane Addams Tollway (formerly Northwest Tollway), John F. Kennedy Expy (cosigned with I-94), Dan Ryan Expy (cosigned with I-94), and Chicago Skyway Toll Bridge.

• I-94 is Tri-State Tollway in Lake County, Edens Spur, Edens Expy, John F. Kennedy Expy (cosigned with I-90), Dan Ryan Expy (cosigned with I-90), Bishop Ford Frwy (formerly Calumet Expy), Kingery Expy (cosigned with I-80) and Borman Expy (cosigned with I-80).
• I-190 is the John F. Kennedy Expy spur heading into Chicago-O'Hare Int'l Airport.
• I-290 is the Dwight D. Eisenhower Expy.
• I-294 is the Tri-State Tollway.

• US Routes in the Illinois part of the area include: US 6, US 12, US 14, US 20, US 30, US 34, US 41, US 45, and US 52.
• Illinois Route 53, an arterial north–south state highway running through Grundy, Will, DuPage, Cook and Lake counties
• Historic US Route 66's eastern terminus is in Chicago.

In addition to the Chicago Loop, the metro area is home to a few important subregional corridors of commercial activities. Among them are:

• Illinois Technology and Research Corridor, along the Ronald Reagan Memorial Tollway (Interstate 88)
• Golden Corridor, along the Jane Addams Memorial Tollway (Interstate 90)
• Lakeshore Corridor, along the Edens Expressway and Tri-State Tollway

Listing of the professional sports teams in the Chicago metropolitan area

Major league professional teams:

• Major League Baseball (MLB)
  • Chicago Cubs
  • Chicago White Sox
• National Football League (NFL)
  • Chicago Bears
• National Basketball Association (NBA)
  • Chicago Bulls
• National Hockey League (NHL)
  • Chicago Blackhawks
• Major League Soccer (MLS)
  • Chicago Fire FC

Other professional teams:

• Women's National Basketball Association (WNBA)
  • Chicago Sky
• National Women's Soccer League (NWSL)
  • Chicago Stars FC
• American Association of Professional Baseball (AA)
  • Chicago Dogs
  • Kane County Cougars
  • Gary SouthShore RailCats
• American Hockey League (AHL)
  • Chicago Wolves
• NBA G League (NBAGL)
  • Windy City Bulls
• Major League Rugby (MLR)
  • Chicago Hounds

The Chicagoland Speedway oval track has hosted NASCAR Cup Series and IndyCar Series races. The Chicago Marathon is one of the World Marathon Majors. The Western Open and BMW Championship are PGA Tour tournaments that have been held primarily at golf courses near Chicago.

NCAA Division I College Sports Teams:

• Atlantic 10 Conference
  • Loyola University Chicago Ramblers
• Big East Conference
  • DePaul University Blue Demons
• Big Ten Conference
  • Northwestern University Wildcats (Evanston)
• Mid-American Conference
  • Northern Illinois University Huskies (DeKalb)
• Missouri Valley Conference
  • University of Illinois Chicago Flames
  • Valparaiso University Beacons (Valparaiso, IN)
• Northeast Conference
  • Chicago State University Cougars

• Chicago-style hot dog
• Chicago-style pizza
• Italian beef
• Caramel popcorn

The two main newspapers are the Chicago Tribune and the Chicago Sun-Times. Local television channels broadcasting to the Chicago market include WBBM-TV 2 (CBS), WMAQ-TV 5 (NBC), WLS-TV 7 (ABC), WGN-TV 9 (Ind), WTTW 11 (PBS), MeTV 23, WCIU 26 (CW), WFLD 32 (FOX), WCPX-TV 38 (Ion), WSNS-TV 44 (Telemundo), WPWR-TV 50 (MyNetworkTV), and WJYS-TV 62 (The Way). Radio stations serving the area include: WBBM (AM), WBEZ, WGN (AM), WMBI, WLS (AM), and WSCR.

Elementary and secondary education within the Chicago metropolitan area is provided by dozens of different school districts, of which by far the largest is the Chicago Public Schools with 400,000 students.^[42] Numerous private and religious school systems are also found in the region, as well as a growing number of charter schools. Racial inequalities in education in the region remain widespread, often breaking along district boundaries;^[43] for instance, educational prospects vary widely for students in the Chicago Public Schools compared to those in some neighboring suburban schools.^[44]

Historically, the Chicago metropolitan area has been at the center of a number of national educational movements, from the free-flowing Winnetka Plan to the regimented Taylorism of the Gary Plan.^[45] In higher education, University of Chicago founder William Rainey Harper was a leading early advocate of the junior college movement; Joliet Junior College is the nation's oldest continuously operating junior college today.^[46] Later U of C president Robert Maynard Hutchins was central to the Great Books movement, and programs of dialogic education arising from that legacy can be found today at the U of C, at Shimer College,^[47] and in the City Colleges of Chicago and Oakton College in the Northwest suburbs.^[48]

From 1947 until 1988, the Illinois portion of the Chicago metro area was served by a single area code, 312, which abutted the 815 area code. In 1988 the 708 area code was introduced and the 312 area code became exclusive to the city of Chicago.

It became common to call suburbanites "708'ers", in reference to their area code.

The 708 area code was partitioned in 1996 into three area codes, serving different portions of the metro area: 630, 708, and 847.

At the same time that the 708 area code was running out of phone numbers, the 312 area code in Chicago was also exhausting its supply of available numbers. As a result, the city of Chicago was divided into two area codes, 312 and 773. Rather than divide the city by a north–south area code, the central business district retained the 312 area code, while the remainder of the city took the new 773 code.

In 2002, the 847 area code was supplemented with the overlay area code 224. In February 2007, the 815 area code (serving outlying portions of the metro area) was supplemented with the overlay area code 779. In October 2007, the overlay area code 331 was implemented to supplement the 630 area with additional numbers.

Plans are in place for overlay codes in the 708, 773, and 312 regions as those area codes become exhausted in the future.

• 312 Chicago - City (The Loop and central neighborhoods, e.g. the Near North Side)
• 773 Chicago - City (Everywhere else within the city limits, excluding central area)
• 872 Chicago - City (overlay for 312 & 773, effective November 7, 2009)
• 847/224 (North and Northwest Suburbs)
• 630/331 (Outer Western Suburbs)
• 708 (South and Near West Suburbs)
• 815/779 (Rockford & Joliet: Far Northwest/Southwest Suburbs)
• 219 (Northwest Indiana)
• 574 (North-central Indiana)
• 262 (Southeast Wisconsin surrounding Milwaukee County)

• 464 overlay for 708 (January 21, 2022, rollout)

• Index of Illinois-related articles

• Fischer, Paul B. (July 28, 1993). Racial and Locational Patterns of Subsidized Housing in the Chicago Suburbs: A Report to the MacArthur Foundation (Archive). Lake Forest, Ill.: Lake Forest College. Report to the MacArthur Foundation.
• Lewinnek, Elaine (2014). The Working Man's Reward: Chicago's Early Suburbs and the Roots of American Sprawl. Oxford: Oxford University Press.

• Encyclopedia of Chicago (2004), comprehensive coverage of city and suburbs, past and present
• U.S. Census Urbanized Area Outline Map (2000)
• Chicago-Naperville-Michigan City, IL-IN-WI Combined Statistical Area (2012) map
• Illinois CBSAs and Counties (2013) map
• U.S. Census Bureau Chicago city, Illinois QuickFacts
• Metropolitan and Micropolitan Statistical Areas
• About Metropolitan and Micropolitan Statistical Areas
• History of Metropolitan Areas
• Metropolitan and Micropolitan Statistical Areas Population Totals and Components of Change: 2010–2019

 

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The purpose of building codes is to provide minimum standards for safety, health, and general welfare including structural integrity, mechanical integrity (including sanitation, water supply, light, and ventilation), means of egress, fire prevention and control, and energy conservation.^[9][10] Building codes generally include:

• Standards for structure, placement, size, usage, wall assemblies, fenestration size/locations, egress rules, size/location of rooms, foundations, floor assemblies, roof structures/assemblies, energy efficiency, stairs and halls, mechanical, electrical, plumbing, site drainage & storage, appliance, lighting, fixtures standards, occupancy rules, and swimming pool regulations
• Rules regarding parking and traffic impact
• Fire code rules to minimize the risk of a fire and to ensure safe evacuation in the event of such an emergency^{[citation needed]}
• Requirements for earthquake (seismic code), hurricane, flood, and tsunami resistance, especially in disaster prone areas or for very large buildings where a failure would be catastrophic^{[citation needed]}
• Requirements for specific building uses (for example, storage of flammable substances, or housing a large number of people)
• Energy provisions and consumption
• Grandfather clauses: Unless the building is being renovated, the building code usually does not apply to existing buildings.
• Specifications on components
• Allowable installation methodologies
• Minimum and maximum room ceiling heights, exit sizes and location
• Qualification of individuals or corporations doing the work
• For high structures, anti-collision markers for the benefit of aircraft

Building codes are generally separate from zoning ordinances, but exterior restrictions (such as setbacks) may fall into either category.

Designers use building code standards out of substantial reference books during design. Building departments review plans submitted to them before construction, issue permits [or not] and inspectors verify compliance to these standards at the site during construction.

There are often additional codes or sections of the same building code that have more specific requirements that apply to dwellings or places of business and special construction objects such as canopies, signs, pedestrian walkways, parking lots, and radio and television antennas.

Building codes have been criticized for contributing to housing crisis and increasing the cost of new housing to some extent, including through conflicting code between different administrators.^[11] Proposed improvements include regular review and cost-benefit analysis of building codes,^[12] promotion of low-cost construction materials and building codes suitable to mass production,^[11] reducing bureaucracy, and promoting transparency.^[13]

Building codes have a long history. The earliest known written building code is included in the Code of Hammurabi,^[3] which dates from circa 1772 BC.

The book of Deuteronomy in the Hebrew Bible stipulated that parapets must be constructed on all houses to prevent people from falling off.^[14]

In the Chinese book of rites it mentions that ancestral temples and houses should be a certain standard length in ancient China they measured land in the chu or well field system so it was important to be precise though most of the actual lengths are lost or obscure.^[15][16]

In ancient Japan a certain official destroyed a courtiers house because the size was above his rank.^[17]

In Paris, under the reconstruction of much of the city under the Second Empire (1852–70), great blocks of apartments were erected^[18] and the height of buildings was limited by law to five or six stories at most.

After the Great Fire of London in 1666, which had been able to spread so rapidly through the densely built timber housing of the city, the Rebuilding of London Act 1666 was passed in the same year as the first significant building regulation.^[19] Drawn up by Sir Matthew Hale, the act regulated the rebuilding of the city, required housing to have some fire resistance capacity and authorised the City of London Corporation to reopen and widen roads.^[20] The Laws of the Indies were passed in the 1680s by the Spanish Crown to regulate the urban planning for colonies throughout Spain's worldwide imperial possessions.

The first systematic national building standard was established with the Metropolitan Buildings Act 1844. Among the provisions, builders were required to give the district surveyor two days' notice before building, regulations regarding the thickness of walls, height of rooms, the materials used in repairs, the dividing of existing buildings and the placing and design of chimneys, fireplaces and drains were to be enforced and streets had to be built to minimum requirements.^[21]

The Metropolitan Buildings Office was formed to regulate the construction and use of buildings throughout London. Surveyors were empowered to enforce building regulations, which sought to improve the standard of houses and business premises, and to regulate activities that might threaten public health. In 1855 the assets, powers and responsibilities of the office passed to the Metropolitan Board of Works.

The City of Baltimore passed its first building code in 1891.^[22] The Great Baltimore Fire occurred in February 1904. Subsequent changes were made that matched other cities.^[23] In 1904, a Handbook of the Baltimore City Building Laws was published. It served as the building code for four years. Very soon, a formal building code was drafted and eventually adopted in 1908.

The structural failure of the tank that caused the Great Molasses Flood of 1919 prompted the Boston Building Department to require engineering and architectural calculations be filed and signed. U.S. cities and states soon began requiring sign-off by registered professional engineers for the plans of major buildings.^[24]

More recently, the 2015 Berkeley balcony collapse has prompted updates to California's balcony building codes, set for 2025, which include stricter material requirements, enhanced load-bearing standards, and mandatory inspections which known as SB326 and SB721.^[25]These laws mandate regular inspections every six years for multifamily buildings. Property owners and HOAs are required to address any structural or waterproofing issues identified during inspections to ensure compliance and safety. Failure to comply can result in fines, increased liability, and legal consequences. The updates aim to prevent tragedies like the Berkeley collapse, which was caused by dry rot and structural failure, by ensuring the long-term safety and durability of elevated structures.^[26]

The current energy codes^{[clarification needed]} of the United States are adopted at the state and municipal levels and are based on the International Energy Conservation Code (IECC). Previously, they were based on the Model Energy Code (MEC). As of March 2017, the following residential codes have been partially or fully adopted by states:^[27]

• 2015 IECC or equivalent (California, Illinois, Maryland, Massachusetts, Michigan, Pennsylvania, New Jersey, New York, Vermont, Washington)
• 2012 IECC or equivalent (Alabama, Connecticut, Delaware, District of Columbia, Florida, Iowa, Minnesota, Nevada, Rhode Island, Texas)
• 2009 IECC or equivalent (Arkansas, Georgia, Idaho, Indiana, Kentucky, Louisiana, Montana, Nebraska, New Hampshire, New Mexico, North Carolina, Ohio, Oklahoma, Oregon, South Carolina, Tennessee, Virginia, West Virginia, Wisconsin)
• 2006 IECC or equivalent (Utah)
• 2006 IECC or no statewide code (Alaska, Arizona, Colorado, Kansas, Maine, Mississippi, Missouri, North Dakota, South Dakota, Wyoming)

Australia uses the National Construction Code.

• Building officials
• Construction law
• Earthquake-resistant structures
• Energy Efficiency and Conservation Block Grants
• Outline of construction
• Seismic code
• Uniform Mechanical Code
• Variance (land use) – permission to vary zoning and sometimes building to code

• IAPMO Website
• IAPMO Codes Website