Illinois
state of the United States of America

Illinois ( IL-ih-NOY) is a state in the Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash and Ohio rivers to its south. Of the fifty U.S. states, Illinois has the fifth-largest gross domestic product (GDP), the sixth-largest population, and the 25th-most land area. Its capital city is Springfield in the center of the state, and the state's largest city is Chicago, located in northeastern Illinois.
Present-day Illinois was inhabited by Indigenous cultures for thousands of years. The French were the first Europeans to arrive, settling near the Mississippi and Illinois rivers in the 17th-century Illinois Country, as part of their sprawling colony of New France. A century later, the revolutionary war Illinois campaign prefigured American involvement in the region. Following U.S. independence in 1783, which made the Mississippi River the national boundary, American settlers began arriving from Kentucky via the Ohio River. Illinois was soon part of the United States' oldest territory, the Northwest Territory, and in 1818, it achieved statehood. The Erie Canal brought increased commercial activity in the Great Lakes, and the invention of the self-scouring steel plow by Illinoisan John Deere turned the state's rich prairie into some of the world's most productive and valuable farmland, attracting immigrant farmers from Germany, Sweden, Hungary, and elsewhere.
“Illinois” enters the record as state of the United States of America. Crown Archives preserves that source wording while asking what Illinois, state and United can confirm, complicate or overturn.
Why this record matters
“Illinois” is worth following because a concise public description often conceals a longer documentary argument. Here, Illinois, state and United provides the most credible route into that argument.
Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Sep 25, 2026. The linked authority identifier is Q1204. VIAF identifies the subject as 138972861. The Library of Congress control number is n79053746. Authority coordinates are 40.000, -89.250. 2 of 5 selected statements include explicit references; 2 carry qualifiers and 0 use preferred rank. The first chronological checks are 1783 and 1818.
A concise general-reference account can conceal disagreements about scope, terminology or the weight assigned to individual sources. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
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The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Illinois”, its source revision and the description used here.
- Expand the search: follow Illinois primary sources, Illinois archive and Illinois research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
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This entry incorporates text from “Illinois” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.