The city of

Chicago (''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name ...

is located in northern

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolita ...

, United States, at the south western tip of

Lake Michigan Lake Michigan is one of the five Great Lakes of North America. It is the second-largest of the Great Lakes by volume () and the third-largest by surface area (), after Lake Superior and Lake Huron. To the east, its basin is conjoined with that o ...

. It sits on the

Saint Lawrence Seaway The St. Lawrence Seaway (french: la Voie Maritime du Saint-Laurent) is a system of locks, canals, and channels in Canada and the United States that permits oceangoing vessels to travel from the Atlantic Ocean to the Great Lakes of North Americ ...

continental divide A continental divide is a drainage divide on a continent such that the drainage basin on one side of the divide feeds into one ocean or sea, and the basin on the other side either feeds into a different ocean or sea, or else is endorheic, not ...

at the site of the

Chicago Portage The Chicago Portage was an ancient portage that connected the Great Lakes waterway system with the Mississippi River system. Connecting these two great water trails meant comparatively easy access from the mouth of the St Lawrence River on the At ...

, an ancient

trade route A trade route is a logistical network identified as a series of pathways and stoppages used for the commercial transport of cargo. The term can also be used to refer to trade over bodies of water. Allowing goods to reach distant markets, a sing ...

connecting the

Mississippi River The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it f ...

and the

Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...

watersheds.

Geography

Chicago's present natural geography is a result of the large

glaciers A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as ...

of the

Ice Age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...

, namely the

Wisconsinan Glaciation The Wisconsin Glacial Episode, also called the Wisconsin glaciation, was the most recent glacial period of the North American ice sheet complex. This advance included the Cordilleran Ice Sheet, which nucleated in the northern North American Cor ...

that carved out the modern basin of

(which formed from the glacier's meltwater). The city of Chicago itself sits on the Chicago Plain, a flat plain that was once the bottom of ancestral

Lake Chicago Lake Chicago was a prehistoric proglacial lake that is the ancestor of what is now known as Lake Michigan, one of North America's five Great Lakes. Fed by retreating glaciers, it drained south through the Chicago Outlet River. Origin The cit ...

. This plain has very little topographical relief; in fact, topographical relief is so unusual in the plain that what would be unnoticed hills and ridges in other locales have been given names. The highest natural point within the city limits is in the Beverly neighborhood at at . In pioneer days, this hill was called

Blue Island Blue Island is a city in Cook County, Illinois, located approximately south of Chicago's Loop. Blue Island is adjacent to the city of Chicago and shares its northern boundary with that city's Morgan Park neighborhood. The population was 22,558 ...

, so named because at a distance it looked like an island set in a trackless prairie sea. In fact, it and the nearby Stony Island were both islands in Lake Chicago as it receded. On the North side, the diagonals Clark Street and Ridge Boulevard run along ridges that were once sandbars in the Lake. One special feature of the Chicago area was the now-vanished Mud Lake in the

Des Plaines River The Des Plaines River () is a river that flows southward for U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map , accessed May 13, 2011 through southern Wisconsin and northern Illinois''American Her ...

watershed. During heavy periods of rain or when the Des Plaines overflowed its banks due to downstream ice dams in the early spring, the river would flow through Mud Lake to the South Branch of the Chicago River, forming a favorite portage for early traders and creating the path of the future I&M and

Chicago Sanitary and Ship Canal The Chicago Sanitary and Ship Canal, historically known as the Chicago Drainage Canal, is a canal system that connects the Chicago River to the Des Plaines River. It reverses the direction of the Main Stem and the South Branch of the Chicago R ...

s. When the city we know today was initially founded in the 1830s, the land was swampy and most of the early building began on low dunes around the

Chicago River The Chicago River is a system of rivers and canals with a combined length of that runs through the city of Chicago, including its center (the Chicago Loop). Though not especially long, the river is notable because it is one of the reasons for ...

's mouth. Indeed, Chicago's low lying geography, which ultimately became crucial to its boom town development (as the site of the

and canal), could not initially attract substantial early settlement because the tall grass prairie around its lake and river systems was underlain by hard packed glacial clay, making much of the area forbidding wetlands. Thus, the paradox of Chicago's development as a city in the 19th century became taking advantage of this geography, but also overcoming its limitations. North of the city of Chicago, there are steep bluffs and ravines that run along Lake Michigan. In contrast, south of the city of Chicago into

Northwest Indiana Northwest Indiana, nicknamed The Region after the Calumet Region, comprises Lake, Porter, LaPorte, Newton and Jasper counties in Indiana. This region neighbors Lake Michigan and is part of the Chicago metropolitan area. According to the 2020 Ce ...

it is without bluffs, but instead has sand dunes. The greatest example of these can be seen at

Indiana Dunes National Park Indiana Dunes National Park is a United States national park located in northwestern Indiana managed by the National Park Service. It was authorized by Congress in 1966 as the Indiana Dunes National Lakeshore and was redesignated as the nation ...

, where some dunes reach up to almost 200 feet. Farther inland, a series of

moraines A moraine is any accumulation of unconsolidated debris (regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice shee ...

surrounds the Chicago Plain. This surrounding area is hilly and higher than the Chicago Plain. Past the moraines, the land flattens out again, but is interspersed with a few deep river valleys such as the

Illinois River The Illinois River ( mia, Inoka Siipiiwi) is a principal tributary of the Mississippi River and is approximately long. Located in the U.S. state of Illinois, it has a drainage basin of . The Illinois River begins at the confluence of the D ...

, Fox River,

, and

Kankakee River The Kankakee River is a tributary of the Illinois River, approximately long, in the Central Corn Belt Plains of northwestern Indiana and northeastern Illinois in the United States. At one time, the river drained one of the largest wetlands in N ...

. Here you may find rock cliffs and rock ravines, which are absent from the interior Chicago area (the ravines of the north shore and south suburbs are soil ravines without any rock). ChicagoILMap

Also, a very large limestone quarry (

Thornton Quarry Thornton Quarry is one of the largest aggregate quarries in the world, located in Thornton, Illinois just south of Chicago. The quarry is 1.5 miles (2.5 km) long, 0.5 miles (1 km) wide, and 450 feet (137.16 m) deep at its deepest poin ...

) exists just south of the city of Chicago in the suburb of Thornton. It was once a coral reef when the Midwest was covered by a warm inland sea (hundreds of millions of years before the glaciation of the Chicago area). The rest of the Chicago area does not have bedrock this close to the surface.

Climate

The city lies within the

humid continental climate A humid continental climate is a climatic region defined by Russo-German climatologist Wladimir Köppen in 1900, typified by four distinct seasons and large seasonal temperature differences, with warm to hot (and often humid) summers and freezing ...

zone, and experiences four distinct

season A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region. On Earth, seasons are the result of the axial parallelism of Earth's tilted orbit around the Sun. In temperate and pol ...

s. Summers are warm and humid with a July average of . Winters are cold, snowy and windy with temperatures below freezing. Spring and fall are mild with moderate humidity. According to the

National Weather Service The National Weather Service (NWS) is an Government agency, agency of the Federal government of the United States, United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weathe ...

, Chicago's highest official temperature reading of was recorded on June 1, 1934. The lowest temperature of was recorded on January 20, 1985. Along with long, hot dry spells in the summer, Chicago can suffer extreme winter cold spells. In the entire month of January 1977, the temperature did not rise above . The average temperature that month was around . Chicago's yearly

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...

averages about 34 inches (860 millimeters). Summer is typically the rainiest season, with short-lived rainfall and

thunderstorm A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are someti ...

s more common than prolonged rainy periods. Winter precipitation tends to be more

snow Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout ...

than rain. Chicago's snowiest winter on record was that of 1978–79, with of snow in total. The winter of 2007–08, with more than of snow, was the snowiest in nearly three decades, and the winter of 2008/2009 produced just over . This marked the first time in three decades that back-to-back winters produced 50 inches or more of snow. Average winter snowfall is normally, depending on the reporting location, . The highest one-day snowfall total in Chicago history was on January 2, 1999. Chicago's highest one-day rainfall total was on September 13, 2008.
''National Weather Service Weather Forecast Office - Chicago, IL. The previous record of had been set on August 14, 1987. The record for yearly rainfall is set in 2008; 1983 was the wettest year before with .

Statistics

According to the

United States Census Bureau The United States Census Bureau (USCB), officially the Bureau of the Census, is a principal agency of the U.S. Federal Statistical System, responsible for producing data about the American people and economy. The Census Bureau is part of the ...

, the City of Chicago has a total area of 606.1 km² (234.0 mi²). 588.3 km² (227.1 mi²) of it is land and of it is water. The total area is 2.94% water. The city has been built on relatively flat land, the average height of land is above sea level. The

centroid In mathematics and physics, the centroid, also known as geometric center or center of figure, of a plane figure or solid figure is the arithmetic mean position of all the points in the surface of the figure. The same definition extends to any ob ...

(geographical center) of the city is at , southeast of 28th and Leavitt Streets in an industrial area near the

. (Before annexations in the 1950s, notably for

O'Hare International Airport Chicago O'Hare International Airport , sometimes referred to as, Chicago O'Hare, or simply O'Hare, is the main international airport serving Chicago, Illinois, located on the city's Northwest Side, approximately northwest of the Chicago Loop, ...

, references placed the geographical center near 37th and Honore Streets.) Chicago, along with

New York City New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...

and

Los Angeles, California Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world' ...

are the three most populous cities of the U.S., yet Chicago is only half the other two cities' individual land areas. Chicago's nickname, "The Windy City," actually acquired from a political op-ed piece, fits the city well as its location on Lake Michigan moderates the climate and often provides a breeze. The Chicago

Metropolitan Statistical Area In the United States, a metropolitan statistical area (MSA) is a geographical region with a relatively high population density at its core and close economic ties throughout the area. Such regions are neither legally Incorporated town, incorporate ...

(MSA) consists of

Cook county Cook County is the most populous county in the U.S. state of Illinois and the second-most-populous county in the United States, after Los Angeles County, California. More than 40% of all residents of Illinois live within Cook County. As of 20 ...

and five surrounding Illinois counties as well as the Chicago–Gary–Kenosha

Combined Statistical Area Combined statistical area (CSA) is a United States Office of Management and Budget (OMB) term for a combination of adjacent metropolitan (MSA) and micropolitan statistical areas (µSA) across the 50 US states and the territory of Puerto Ric ...

(CSA) which is made up of nine counties, two of them in northwestern

Indiana Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th s ...

and one in southeastern

Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...

Cityscape

After building the first ever skyscraper (

Home Insurance Building The Home Insurance Building was a skyscraper that stood in Chicago from 1885 to 1931. Originally ten stories and tall, it was designed by William Le Baron Jenney in 1884 and completed the next year. Two floors were added in 1891, bringing its ...

), Chicago has been at the forefront of skyscraper building ever since. Today Chicago can boast to having 2 of the 10

tallest buildings in the United States The world's first skyscraper was built in Chicago in 1885. Since then, the United States has been home to some of the world's tallest skyscrapers. New York City, specifically the borough of Manhattan, notably has the tallest skyline in the cou ...

and 9 of the 100

in the world ''In the World'' is an album by jazz saxophonist Clifford Jordan which was recorded in 1969 and released on the Strata-East label in 1972. The album was rereleased on CD as part of ''The Complete Clifford Jordan Strata-East Sessions'' by Mosaic ...

. By modern standards, Chicago has little reason to build up: being located in the

Midwest The Midwestern United States, also referred to as the Midwest or the American Midwest, is one of four Census Bureau Region, census regions of the United States Census Bureau (also known as "Region 2"). It occupies the northern central part of ...

, it has plenty of room to sprawl outwards on almost Euclideanesque flat ground. There is the

, which may bring some argument as to geographic restriction, but the impact of which was strongly lessened by the strict adherence to the Chicago grid across the river. Today, Chicago is going through a massive skyscraper building boom, with projects like 55 East Erie (the tallest residential building in the U.S. outside New York City) and Trump International Hotel (completed in August 2008, it is the second tallest in Chicago and the tallest building built in the U.S. for nearly three decades) breaking ground frequently. This can be attributed to the precedent that Chicago has always had a history of frantic skyscraper building, mostly beginning after the

Great Chicago Fire The Great Chicago Fire was a conflagration that burned in the American city of Chicago during October 8–10, 1871. The fire killed approximately 300 people, destroyed roughly of the city including over 17,000 structures, and left more than 10 ...

when the price of land in the city increased dramatically. This caused architects to start building upward. Since this time developers simply follow the pattern set before them.

Ecology

Chicago lies between the

Temperate deciduous forest Temperate deciduous or temperate broad-leaf forests are a variety of temperate forest 'dominated' by trees that lose their leaves each year. They are found in areas with warm moist summers and cool winters. The six major areas of this forest type ...

and

Temperate grassland Temperate grasslands, savannas, and shrublands is a terrestrial biome defined by the World Wide Fund for Nature. The predominant vegetation in this biome consists of grass and/or shrubs. The climate is temperate and ranges from semi-arid to semi ...

zone (specifically Central forest–grasslands transition, which traditionally feature

tall grass prairie The tallgrass prairie is an ecosystem native to central North America. Historically, natural and anthropogenic fire, as well as grazing by large mammals (primarily bison) provided periodic disturbances to these ecosystems, limiting the encroac ...

). Trees native to the area, which are all

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...

, include:Increasing Tree Diversity in Chicago’s Landscape -Plant Native Non-Invasive Urban Tolerant Trees
Robert H. Mohlenbrock @ USDA-NRCS PLANTS Database / USDA SCS. 1989. Midwest wetland flora: Paul Wray, Iowa State University, Missouri Botanical Garden PlantFinder Sycamore Platanus occidentalis

Acer negundo ''Acer negundo'', the box elder, boxelder maple, Manitoba maple or ash-leaved maple, is a species of maple native to North America. It is a fast-growing, short-lived tree with opposite, compound leaves. It is sometimes considered a weedy or inv ...

Acer rubrum ''Acer rubrum'', the red maple, also known as swamp maple, water maple, or soft maple, is one of the most common and widespread deciduous trees of eastern and central North America. The U.S. Forest Service recognizes it as the most abundant nati ...

Acer saccharinum ''Acer saccharinum'', commonly known as silver maple, creek maple, silverleaf maple, soft maple, large maple, water maple, swamp maple, or white maple, is a species of maple native to the eastern and central United States and southeastern Canad ...

Betula papyrifera ''Betula papyrifera'' (paper birch, also known as (American) white birch and canoe birch) is a short-lived species of birch native to northern North America. Paper birch is named for the tree's thin white bark, which often peels in paper like ...

Celtis occidentalis ''Celtis occidentalis'', commonly known as the common hackberry, is a large deciduous tree native to North America. It is also known as the nettletree, sugarberry, beaverwood, northern hackberry, and American hackberry. It is a moderately long-l ...

Fagus grandifolia ''Fagus grandifolia'', the American beech or North American beech, is a species of beech tree native to the eastern United States and extreme southeast of Canada. Description ''Fagus grandifolia'' is a large deciduous tree growing to tall, w ...

Fraxinus pennsylvanica ''Fraxinus pennsylvanica'', the green ash or red ash, is a species of ash native to eastern and central North America, from Nova Scotia west to southeastern Alberta and eastern Colorado, south to northern Florida, and southwest to Oklahoma and e ...

Juglans nigra ''Juglans nigra'', the eastern American black walnut, is a species of deciduous tree in the walnut family, Juglandaceae, native to North America. It grows mostly in riparian zones, from southern Ontario, west to southeast South Dakota, south to ...

Ostrya virginiana ''Ostrya virginiana'', the American hophornbeam, is a species of ''Ostrya'' native to eastern North America, from Nova Scotia west to southern Manitoba and eastern Wyoming, southeast to northern Florida and southwest to eastern Texas. Populations ...

Quercus imbricaria ''Quercus imbricaria'', the shingle oak, is a deciduous tree in the red oak group of oaks. It is native primarily to the Midwestern and Upper South regions of North America. Description A tree usually 15–18 meters (50–60 feet) high, maxi ...

Platanus occidentalis ''Platanus occidentalis'', also known as American sycamore, American planetree, western plane, occidental plane, buttonwood, and water beech, is a species of ''Platanus'' native to the eastern and central United States, the mountains of northeas ...

Populus tremuloides ''Populus tremuloides'' is a deciduous tree native to cooler areas of North America, one of several species referred to by the common name aspen. It is commonly called quaking aspen, trembling aspen, American aspen, mountain or golden aspen, tr ...

Sassafras albidum ''Sassafras albidum'' (sassafras, white sassafras, red sassafras, or silky sassafras) is a species of ''Sassafras'' native to eastern North America, from southern Maine and southern Ontario west to Iowa, and south to central Florida and eastern T ...

Tilia americana ''Tilia americana'' is a species of tree in the family Malvaceae, native to eastern North America, from southeast Manitoba east to New Brunswick, southwest to northeast Oklahoma, southeast to South Carolina, and west along the Niobrara River to ...

Ulmus americana ''Ulmus americana'', generally known as the American elm or, less commonly, as the white elm or water elm, is a species of elm native to eastern North America, naturally occurring from Nova Scotia west to Alberta and Montana, and south to Flor ...

Viburnum lentago ''Viburnum lentago'', the nannyberry, sheepberry, or sweet viburnum, is a species of ''Viburnum'' native to North America. Description It is a large shrub or small tree growing upwards to tall with a trunk up to in diameter and a short trun ...

Notes

References

{{DEFAULTSORT:Geography Of Chicago