Illinois River
Illinois tributary of the Mississippi River in the United States
The Illinois River (Miami-Illinois: Inoka Siipiiwi) is a principal tributary of the Mississippi River at approximately 273 miles (439 km) in length. Located in the U.S. state of Illinois, the river has a drainage basin of 28,756.6 square miles (74,479 km2). The Illinois River begins with the confluence of the Des Plaines and Kankakee rivers in the Chicago metropolitan area, and it generally flows to the southwest across Illinois, until it empties into the Mississippi near Grafton, Illinois. Its drainage basin extends into southeastern Wisconsin, northwestern Indiana, and a very small area of southwestern Michigan in addition to central Illinois. Along its banks are several river ports, including the largest, Peoria, Illinois. Historic and recreation areas on the river include Starved Rock, and the internationally important wetlands of the Emiquon Complex and Dixon Waterfowl Refuge.
The river was important among Native Americans and French traders as the principal water route connecting the Great Lakes with the Mississippi. The French colonial settlements along these rivers formed the heart of the area known as the Illinois Country in the 17th and 18th centuries. After the construction of the Illinois and Michigan Canal and the Hennepin Canal in the 19th century, the role of the river as link between Lake Michigan and the Mississippi was extended into the era of modern industrial shipping. The Illinois now forms the basis for the Illinois Waterway, extending the river's capabilities for navigation and commercial shipping.
The public source identifies “Illinois River” as illinois tributary of the Mississippi River in the United States. This brief keeps that definition visible, then builds a research path around Illinois, River and tributary.
Why this record matters
A short description can identify a subject without explaining its stakes. For “Illinois River”, the useful work is to connect “illinois tributary of the Mississippi River in the United States” to the records capable of establishing context and consequence.
Maps, plans, fabric surveys and administrative records can establish how the site’s name, extent and function changed over time. The source revision retrieved here is dated Aug 3, 2026. The linked authority identifier is Q8321. The Library of Congress control number is sh85064322. Authority coordinates are 41.394, -88.260. 4 of 4 selected statements include explicit references; 3 carry qualifiers and 0 use preferred rank.
Architectural summaries often privilege surviving fabric and can understate demolished phases, contested use or displaced communities. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Treat names, boundaries and functions as historically changeable. Maps, plans, inventories and administrative records can clarify what the place meant at different dates.
- Historic place names
- Jurisdictional context
- Routes into maps and plans
Contemporary maps, plans, listed-building records, estate papers and the responsible local or national archive.
Three-step research path
- Establish the record: confirm the title “Illinois River”, its source revision and the description used here.
- Expand the search: follow Illinois River primary sources, Illinois River 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
- Which source most directly establishes the central claim about “Illinois River”?
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- Which earlier names or jurisdictions may reveal additional records?
Search terms from this dossier
This entry incorporates text from “Illinois River” 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.