Editing Illinois (section)

===20th century===
[[File:Protestors and Chicago Police Officers in Grant Park - DPLA - 2972723d78e7f60f542da94846a6f9a6 (1) (cropa).jpg|thumb|Police and protesters at the [[1968 Democratic National Convention]] in Chicago.]]
[[File:Alton Illinois sinking in 1993.jpg|thumb|upright|Rising waters in [[Alton, Illinois|Alton]] in 1993.]]
At the turn of the 20th century, Illinois had a population of nearly 5&nbsp;million. Many people from other parts of the country were attracted to the state by employment caused by the expanding industrial base. Whites were 98% of the state's population.<ref name="census">{{cite web |title=Illinois—Race and Hispanic Origin: 1800 to 1990 |publisher=U.S. Census Bureau |url=https://www.census.gov/population/www/documentation/twps0056/twps0056.html |archive-url=https://web.archive.org/web/20080725044857/http://www.census.gov/population/www/documentation/twps0056/twps0056.html |url-status=dead |archive-date=July 25, 2008}}</ref> Bolstered by continued [[History of immigration to the United States|immigration from southern and eastern Europe]], and by the African-American [[Great Migration (African American)|Great Migration]] from the South, Illinois grew and emerged as one of the most important states in the union. By the end of the century, the population had reached 12.4&nbsp;million.

The [[Century of Progress]] [[World's fair]] was held at Chicago in 1933. Oil strikes in [[Marion County, Illinois|Marion County]] and [[Crawford County, Illinois|Crawford County]] led to a boom in 1937, and by 1939, Illinois ranked fourth in U.S. oil production. Illinois manufactured 6.1 percent of total United States military armaments produced during [[World War&nbsp;II]], ranking seventh among the 48 states.<ref>{{cite book|last1=Peck| first1=Merton J.| author-link2=Frederic M. Scherer |last2=Scherer |first2=Frederic M. |title=The Weapons Acquisition Process: An Economic Analysis |year=1962 |publisher=Harvard Business School |page=111}}</ref> Chicago became an ocean port with the opening of the [[Saint Lawrence Seaway]] in 1959. The seaway and the [[Illinois Waterway]] connected Chicago to both the Mississippi River and the [[Atlantic Ocean]]. In 1960, [[Ray Kroc]] opened the first [[McDonald's]] franchise in [[Des Plaines, Illinois|Des Plaines]], which was demolished in 1984.<ref name=":0">{{Cite web |title=McDonald's Store No. 1 (Gone), Des Plaines, Illinois |url=https://www.roadsideamerica.com/story/11370 |access-date=2024-03-12 |website=RoadsideAmerica.com |language=en |archive-date=March 12, 2024 |archive-url=https://web.archive.org/web/20240312024737/https://www.roadsideamerica.com/story/11370 |url-status=live }}</ref> In 1985 a replica was built on the same site to recreate how the original one looked.<ref name=":0" /> Though this replica was demolished in 2017, due to repeated flooding of the building.<ref>{{Cite web |date=2014-02-27 |title=Des Plaines blames Mt. Prospect, Prospect Hts. for heightened flooding - DailyHerald.com |url=https://www.dailyherald.com/article/20130419/news/704199563/ |access-date=2024-03-12 |archive-url=https://web.archive.org/web/20140227181958/https://www.dailyherald.com/article/20130419/news/704199563/ |archive-date=February 27, 2014 }}</ref><ref>{{Cite web |last=Placek |first=Christopher |date=2017-11-20 |title=McDonald's plans to tear down Des Plaines replica restaurant |url=https://www.dailyherald.com/20171120/news/mcdonalds-plans-to-tear-down-des-plaines-replica-restaurant/ |access-date=2024-03-12 |website=Daily Herald |language=en-US |archive-date=March 12, 2024 |archive-url=https://web.archive.org/web/20240312024737/https://www.dailyherald.com/20171120/news/mcdonalds-plans-to-tear-down-des-plaines-replica-restaurant/ |url-status=live }}</ref>

Illinois had a prominent role in the emergence of the [[nuclear age]]. In 1942, as part of the [[Manhattan Project]], the [[Chicago Pile-1|University of Chicago]] conducted the first sustained [[nuclear chain reaction]]. In 1957, [[Argonne National Laboratory]], near [[Chicago]], activated the first experimental nuclear power generating system in the United States. By 1960, the first privately financed nuclear plant in the United States, [[Dresden Nuclear Power Plant|Dresden 1]], was dedicated near [[Morris, Illinois|Morris]]. In 1967, [[Fermilab]], a national nuclear research facility near [[Batavia, Illinois|Batavia]], opened a [[particle accelerator]], which was the world's largest for over 40 years. With eleven plants currently operating, Illinois leads all states in the amount of electricity generated from nuclear power.<ref>{{cite web |url=https://www.comed.com/sites/PartnersBusiness/Documents/EconomicDevelopmentFactSheet.pdf |title=ComEd and Electricity Related Messages for Economic Development |access-date=February 7, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110708180209/https://www.comed.com/sites/PartnersBusiness/Documents/EconomicDevelopmentFactSheet.pdf |archive-date=July 8, 2011}}</ref><ref>{{cite web |url=https://www.comed.com/Documents/about-us/economic-development/ComEd_and_Electricity_Related_EconDev_Messages_-_January_2012.pdf |title=Home &#124; ComEd—An Exelon Company |publisher=ComEd |access-date=February 27, 2016 |url-status=dead |archive-url=https://web.archive.org/web/20130914144313/https://www.comed.com/Documents/about-us/economic-development/ComEd_and_Electricity_Related_EconDev_Messages_-_January_2012.pdf |archive-date=September 14, 2013}}</ref>

In 1961, Illinois became the first state in the nation to adopt the recommendation of the [[American Law Institute]] and pass a comprehensive criminal code revision that repealed the law against [[Sodomy laws in the United States|sodomy]]. The code also abrogated [[common law crime]]s and established an [[age of consent]] of 18.<ref>{{cite web |last=Painter |first=George |title=The History of Sodomy Laws in the United States: Illinois |url=http://www.glapn.org/sodomylaws/sensibilities/illinois.htm#fn73 |website=The Sensibilities of Our Forefathers |publisher=Gay & Lesbian Archives of the Pacific Northwest |access-date=January 12, 2012 |date=August 10, 2004 |archive-url=https://web.archive.org/web/20100515065329/http://www.glapn.org/sodomylaws/sensibilities/illinois.htm#fn73 |archive-date=May 15, 2010 |url-status=dead}}</ref> The state's [[Illinois Constitution|fourth constitution]] was adopted in 1970, replacing the 1870 document.<ref>{{cite journal |last1=Hillard |first1=James |title=The Illinois Constitution: A Primer |journal=Illinois Bar Journal |date=October 2008 |volume=96 |issue=10 |page=494 |url=https://www.isba.org/ibj/2008/10/theillinoisconstitutionaprimer |access-date=November 2, 2019 |archive-url=https://web.archive.org/web/20191102094526/https://www.isba.org/ibj/2008/10/theillinoisconstitutionaprimer |archive-date=November 2, 2019 |url-status=dead}}</ref>

The first [[Farm Aid]] concert was held in [[Champaign, Illinois|Champaign]] to benefit American farmers, in 1985. The worst [[upper Mississippi River]] flood of the century, the [[Great Flood of 1993]], inundated many towns and thousands of acres of farmland.<ref name="Biles" />