Editing Peoria County, Illinois (section)

==History==
{{Expand section|date=August 2008}}
Peoria County was formed in 1825 out of [[Fulton County, Illinois|Fulton County]]. It was named for the [[Peoria people|Peoria]], an [[Illiniwek]] people who lived there. It included most of the western valley of the Illinois River up to the Chicago river portage.

=== Gallery timeline ===
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File:Peoria County Illinois 1825.png|Peoria County at creation, with unorganized territory attached to it.<ref name="CI">White, Jesse.  ''Origin and Evolution of Illinois Counties.'' State of Illinois, March 2010.  [http://www.cyberdriveillinois.com/publications/pdf_publications/ipub15.pdf]</ref>
File:Peoria County Illinois 1826.png|Peoria County 1826–1827. The newly created Mercer and Warren Counties were temporarily attached to Peoria.<ref name=CI/>
File:Peoria County Illinois 1827.png|Peoria County 1827–1830.  The creation of Tazewell County left Peoria with only a small tract of unorganized territory east of the Illinois River, whose border was not defined.
File:Peoria County Illinois 1830.png|In 1830, Warren County organized a government. 
File:Peoria County Illinois 1831.png|In 1831, Peoria County's present borders were established and Mercer County was attached to Warren.
</gallery>