Illinois

A Paleo-Indian culture existed in southern Illinois from about 8000 BCE. The religious center of the Mississippian culture was at Cahokia in the southwest, which around 1050 became the culture’s largest and most influential city; about 1300 it was probably the largest pre-Columbian community north of Mexico. The remains of the city, occupied from 800 to 1400 CE, are now Cahokia Mounds State Historic Site and a UNESCO World Heritage Site.⁠[1][2]

When Europeans arrived, the Native peoples of the region all spoke Algonquian languages: the Kickapoo, Sauk and Fox in the north; the Potawatomi, Ottawa and Ojibwa (Chippewa) along Lake Michigan; the Kaskaskia and Peoria on the central prairies; and the Cahokia and Tamaroa in the south. The Miami and the Illiniwek (Illinois) also lived on the land, and the state’s name comes from the Native American tribe living there when Europeans first explored the area.⁠[1][3]

In 1673 the French explorers Louis Jolliet and Jacques Marquette explored the MississippiMississippiMississippi is a state of the United States on the Gulf of Mexico; Jackson is both its capital and its largest city. It was admitted to the Union on December 10, 1817, as the 20th state, and its population in the 2020 census (April 1, 2020) was 2,961,279.Open the full entry and Illinois rivers, becoming the first Europeans to visit Illinois. René-Robert Cavelier, sieur de La Salle, later established Fort Crèvecoeur near present-day Peoria and built Fort Saint Louis near Ottawa. In the late 1600s French explorers navigating the Illinois River founded settlements at Cahokia and Kaskaskia. In 1717 Illinois became part of the French colony of LouisianaLouisianaLouisiana is a state in the southern United States on the Gulf of Mexico, bordered by Arkansas, Mississippi and Texas; its capital is Baton Rouge and its largest city is New Orleans. It entered the Union on April 30, 1812, as the 18th state, and had a population of 4,657,757 in the 2020 census (April 1, 2020).Open the full entry, and the first slaves were brought to Illinois in 1719.⁠[1][2][3][4]

France controlled the region until 1763, when, after the French and Indian War, it ceded its claim to lands east of the Mississippi to Britain. Most of the French then left, and English settlers moved in from VirginiaVirginiaVirginia, officially the Commonwealth of Virginia, is a U.S. state whose capital is Richmond. It entered the Union on June 25, 1788, as the 10th state, and had a population of 8,631,393 in the 2020 census (April 1, 2020).Open the full entry, TennesseeTennesseeTennessee is a U.S. state in the southeast-central United States, with its capital at Nashville. It was admitted to the Union on June 1, 1796, as the 16th state, and the 2020 census (April 1, 2020) counted 6,910,840 residents.Open the full entry and Kentucky. By 1773 the settlers had declined to about 1,000, plus a few hundred slaves.⁠[5][1][4]

In 1778 American forces captured Kaskaskia, the British seat of government, and Illinois became a county of Virginia. In 1779 Jean-Baptiste-Point Du Sable made the first settlement on the site of Chicago.⁠[1]

Illinois became part of the Northwest Territory in 1783, and the Northwest Territory’s seal came into use in the area in 1788. On July 4, 1800, the Northwest Territory was divided and the Illinois country became part of Indiana Territory.⁠[5][6][1]

On February 3, 1809, Congress passed an act dividing Indiana Territory into two governments, and Illinois Territory was created on March 1, 1809, with its capital at Kaskaskia. It spanned all of present-day Illinois and Wisconsin and parts of MichiganMichiganMichigan is a state of the United States nearly surrounded by the Great Lakes and made up of the Upper and Lower peninsulas; its capital is Lansing and its largest city is Detroit. It was admitted to the Union on January 26, 1837, as the 26th state, and its population in the 2020 census (April 1, 2020) was 10,077,331.Open the full entry and MinnesotaMinnesotaMinnesota is a state in the north-central United States and the most northerly of the 48 contiguous states; its capital is St. Paul and its largest city is Minneapolis. It was admitted to the Union on May 11, 1858, as the 32nd state, and its population in the 2020 census (April 1, 2020) was 5,706,494.Open the full entry. The territorial governor and judges created a territorial seal closely modeled on the earliest seal of the United States.⁠[7][8]

Illinois petitioned for statehood in January 1818, and Nathaniel Pope, the territory’s delegate, presented the request in the House on January 16. On April 18, 1818, President James Monroe signed the act enabling the people of Illinois Territory to form a constitution and state government. The act set the requirements for statehood: defined boundaries, a population of at least 40,000 and the drafting and passage of a constitution. Pope proposed moving the northern boundary about 60 miles north so that the state would reach the Great Lakes.⁠[9][7][10]

A census in June 1818 counted about 35,000 residents; a supplementary count continuing until December 1 reached 40,258.⁠[10]

Delegates to a constitutional convention were elected in July 1818: two from each of the 15 counties, plus one more from each of the three largest, for a total of 33. The convention met at Kaskaskia in August and completed and signed the constitution on August 26. Its structure of government was modeled after OhioOhioOhio is a state in the Midwestern United States; its capital is Columbus. It joined the Union in 1803 as the 17th state, the first carved from the Northwest Territory, and its population in the 2020 census (April 1, 2020) was 11,799,448.Open the full entry’s constitution of 1802, and it gave Black residents the status of indentured servants. The first General Assembly met in October 1818 and appointed the first four justices of the Illinois Supreme Court.⁠[10][6][1]

On November 23, 1818, the U.S. House of Representatives voted 117 to 34 to admit Illinois; the Senate passed the resolution unanimously on December 1, and President James Monroe signed it on December 3. At statehood two-thirds of the population lived along the eastern and western edges of southern Illinois and worked mainly in the fur trade.⁠[9][10][1]

In the 30 years after statehood, Illinois changed from a largely empty frontier into a settled, rapidly developing agricultural state.⁠[11]

In 1824 voters rejected a proposal for a constitutional convention whose implicit purpose was to legalize slavery.⁠[1]

The Black Hawk War of 1832 was the last conflict with Native Americans in Illinois.⁠[1]

Kaskaskia and Vandalia served as the first capitals. Springfield became the capital in 1837, a move influenced by Abraham LincolnAbraham LincolnAbraham Lincoln (February 12, 1809 – April 15, 1865) was the 16th president of the United States (1861–1865). Born to a frontier farming family in Kentucky, he had less than a year of formal schooling, taught himself law, and served in the Illinois legislature and the U.S. House of Representatives before winning the presidency as the Republican candidate in 1860. During the Civil War he preserved the Union, issued the Emancipation Proclamation in 1863 and pushed the Thirteenth Amendment abolishing slavery through Congress. He was shot by John Wilkes Booth at Ford’s Theatre in Washington on April 14, 1865, and died the next day.Open the full entry and other legislators.⁠[2]

The Illinois and Michigan Canal was completed in 1848, linking the Great Lakes with the Mississippi River. The new constitution of that year abolished slavery, although repressive laws limiting the rights of African Americans remained. Large numbers of Germans and Irish settled in northern Illinois after the 1840s.⁠[1][2][4]

In 1860 Abraham Lincoln was elected the 16th president of the United States, and he later led the nation through major crises.⁠[2]

During the Civil War Illinois was politically divided but remained in the Union, with northern Illinois loyal to the Union and to Lincoln. About 250,000 Illinoisans fought for the Union, among them Ulysses S. Grant, and no major battles took place in the state.⁠[5][1][3]

From the 1860s European immigrants and freed Black workers arrived to fill jobs in mills, rail yards and slaughterhouses. The state’s Black population was 29,000 in 1870 and 109,000 by 1910.⁠[1][4]

The Great Chicago FireChicago Fire FCChicago Fire FC is a professional soccer club in Major League Soccer, with its regular home at Soldier Field in Chicago.Open the full entry of 1871 destroyed much of the city, though the Chicago Historic Water Tower survived. The fire was a temporary setback to Chicago’s industrial growth, and the rebuilding produced a modern city with the world’s first skyscrapers; the Home Insurance Building, completed in 1885, is considered the first modern skyscraper.⁠[2][1][3]

A state board of health was created in 1877, and a compulsory school-attendance law was passed in 1883. The Haymarket Riot took place in Chicago in 1886. Hull House opened in Chicago in 1892 as a center for social reform. An 1893 “sweatshop act” provided for factory inspections and restricted child labor, limiting children to 8 hours a day and 48 hours a week. In 1894 the Pullman Strike, which began in Chicago’s Pullman neighborhood, became a nationwide railroad strike.⁠[1][2]

From the 1880s until World War I, immigrants came from Poland, Hungary, Italy, Norway, Sweden, Austria and Russia. In 1910 Germans were the largest foreign-born group, followed by Austrians and Hungarians, then Russians, Scandinavians, Irish and Italians.⁠[4]

In 1893 Chicago hosted the World’s Columbian Exposition, marking the 400th anniversary of Columbus’s arrival in the Americas.⁠[2][1]

The Great Migration began with World War I, bringing a steady flow of African Americans from the South to northern industrial centers.⁠[4]

Route 66 was established in 1926, beginning in downtown Chicago and running west across the state.⁠[2]

In 1937 Cook County Hospital in Chicago opened the first blood bank in the United States.⁠[2]

On December 2, 1942, Enrico Fermi and his team achieved the first controlled nuclear chain reaction beneath Stagg Field at the University of Chicago.⁠[2]

On December 15, 1970, Illinois voters approved a new state constitution.⁠[2]

Chicago’s Sears Tower (now Willis Tower) opened in 1973 and was completed in 1974, and it held the title of world’s tallest building for nearly 25 years.⁠[2]

In 2008 Barack Obama, a former Illinois state senator, was elected the first African American president of the United States.⁠[2]

Illinois marked the 200th anniversary of its statehood on December 3, 2018.⁠[10]

On April 26, 2021, the U.S. Census Bureau released the 2020 census apportionment results. Illinois’s seats in the U.S. House of Representatives fell from 18 after the 2010 census to 17, with an average of 754,279 people per seat, giving it 19 electoral votes in the 2024 and 2028 presidential elections.⁠[12][13][14]

Under Article IV of the current constitution, legislative power is vested in a General Assembly consisting of a Senate and a House of Representatives. The state is divided into 59 Legislative Districts, each electing one senator and each divided into two Representative Districts that elect one representative apiece for two-year terms; senators are elected in three staggered groups and serve two four-year terms and one two-year term in each ten-year redistricting cycle. The Senate thus has 59 members and the House 118, and the General Assembly convenes on the second Wednesday in January each year.⁠[15][16]

As of November 2026 the governor is JB PritzkerJB PritzkerJB Pritzker, full name Jay Robert Pritzker, is a Democratic politician, investor and philanthropist who serves as the 43rd governor of Illinois. He was elected in 2018, took office in 2019 and was re-elected in 2022 and 2026. Born into the family that founded Hyatt Hotels, he co-founded and managed Pritzker Group with his brother and has helped promote startup incubation in Chicago and education philanthropy. His policies as governor have covered labor standards, taxation, and the regulation of digital assets and artificial intelligence.Open the full entry, who was elected in 2018, sworn in as Illinois’s 43rd governor on January 14, 2019, and reelected in 2022.⁠[17]

The state’s highest court is the Illinois Supreme Court, which under Article VI of the constitution consists of seven judges elected from five judicial districts: the Chicago-area district elects three and each of the others one. Justices serve ten-year terms, and the court selects a chief justice from among its members. Below it, the Appellate Court is organized into five districts.⁠[18][19]

In the Census Bureau’s state area measurements (boundaries as of January 1, 2010), Illinois has a total area of 57,914 square miles (149,995 square kilometres), of which 55,519 square miles (143,793 square kilometres) is land and 2,395 square miles (6,202 square kilometres) is water, comprising 820 square miles (2,124 square kilometres) of inland water and 1,575 square miles (4,078 square kilometres) of Great Lakes water.⁠[20]

Rivers include the Illinois, Kaskaskia and Rock, and lakes include Lake Shelbyville, Carlyle Lake and Rend Lake. Much of the state was once covered in prairie grass, and Shawnee National Forest in the south covers parts of 10 counties.⁠[21][3][4]

The 2010 census (April 1, 2010) counted 12,830,632 people in Illinois. The Census Bureau’s Vintage 2025 estimate put the population at 12,719,141 on July 1, 2025, down 0.8% from the April 1, 2020, estimates base of 12,821,741; population density in 2020 was 230.8 people per square mile.⁠[22]

In American Community Survey data for 2020–2024, Illinois had 5,036,449 households; 14.7% of residents were foreign-born, 37.8% of people aged 25 and older held a bachelor’s degree or higher, and median household income was $83,390 (in 2024 dollars).⁠[22]

In the early 21st century African Americans made up about one-sixth of the population, four-fifths of them living in Chicago and Cook County; Hispanics made up another one-sixth, and Asian Americans a smaller share. Methodists have been strong since the early 1800s, the Roman Catholic Archdiocese of Chicago is the second largest in the country by membership, and Chicago also has Protestant, Eastern Orthodox and Jewish congregations as well as Muslim, Buddhist and Bahāʾī centers of worship.⁠[4]

The state falls into three broad regions: the north, a highly urbanized band from Chicago to the Rock Island–Moline complex on the Mississippi, including Kankakee, Joliet and Rockford, with heavy industry and large suburbs; the center, including Springfield, Bloomington-Normal, Peoria, Champaign-Urbana, Danville, Galesburg, Quincy and Decatur, with agriculture as its economic base; and the south, much of it dominated by St. Louis, Missouri, with the medium-sized cities of East St. Louis, Belleville, Alton and Granite City concentrated in just two counties.⁠[4]

U.S. Bureau of Economic Analysis data put Illinois’s nominal gross domestic product (all industry total) at $1,240,982.7 million in 2025, up from $1,175,753.7 million in 2024 and $1,118,158.2 million in 2023.⁠[23]

The economy is diversified across manufacturing, agriculture, finance, mining, transportation, government, technology and services including tourism, making Illinois a microcosm of the national economy. Farms cover about three-fourths of the state’s area; Illinois usually ranks among the leading states in soybean and corn production and is also known for pork, dairy goods, grains and livestock, and family-owned farms make up the largest share of its farms. Peoria and Decatur make earth-moving and farm equipment, and Decatur is a major center of soybean processing and ethanol production.⁠[4]

Illinois holds one-fourth of the nation’s bituminous coal reserves. Petroleum production peaked in 1940 and has declined since, but the state remains a regional refining leader and a top ethanol producer. Nuclear power and coal each generate about half of its electricity, and its 11 nuclear reactors are more than in any other state. The U.S. Department of Energy’s Argonne National Laboratory (near Lemont) and Fermilab (in Batavia) are in the state.⁠[4]

The economy of Champaign-Urbana centers on the University of Illinois, and Southern Illinois University has campuses in Carbondale and Edwardsville.⁠[4]

Illinois is nicknamed the Prairie State, and its state slogan is “Land of Lincoln,” since Abraham Lincoln lived there for 31 years. The state has eighteen official state symbols.⁠[21][24][3][25]

On February 19, 1819, the First General Assembly ordered state officials to obtain a permanent state seal modeled on the Great Seal of the United States. In January 1867 Secretary of State Sharon Tyndale, considering the old seal obsolete, asked Senator Allen C. Fuller to sponsor a bill for a new one; Tyndale had proposed reversing the words of the motto, but on March 7, 1867, the Senate amended and passed the bill, restoring the original motto, “State Sovereignty, National Union.” The design adopted in 1868 gave “National Union” greater prominence and printed “Sovereignty” upside down, and although the seal has since been recut, the design has remained essentially unchanged. The seal’s ring reads “Seal of the State of Illinois, Aug. 26th 1818,” and the rock bears the years 1818 and 1868.⁠[6][21]

The state flag grew out of a design contest led by Ella Park Lawrence, state regent of the Daughters of the American Revolution: of 35 designs, the entry by Lucy Derwent of the Rockford chapter was chosen, State Senator Raymond D. Meeker introduced the bill, and it became law without Governor Edward F. Dunne’s signature on July 6, 1915. Because the flag was often mistaken for those of other states, Governor Richard B. Ogilvie approved a bill on September 17, 1969, authorizing a flag bearing the word “Illinois”; a design submitted by Mrs. Sanford Hutchison was accepted, and the new flag became official on July 1, 1970.⁠[26]

The state bird, the northern cardinal, was chosen by Illinois schoolchildren from a list. The state flower, the violet, won a 1907 schoolchildren’s vote with 16,583 votes, ahead of the wild rose (12,628) and goldenrod (4,315), and was made official by a 1908 law. The state tree was designated “Native Oak” in 1908 and changed to the white oak in 1973. The state snack is popcorn.⁠[27][28][29][3]

State of Illinois: Official website: https://www.illinois.gov/ (opens in a new window).⁠[19]

Office of Governor JB Pritzker: Official website: https://gov.illinois.gov/ (opens in a new window).⁠[30]

Illinois General Assembly: Official website: https://www.ilga.gov/ (opens in a new window).⁠[31]