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History and Facts of Illinois Counties

Illinois Counties – In 1673, Louis Joliet and Jacques Marquette became the first Europeans to visit the area that is now Illinois. Cahokia, which was located near what is now the eastern part of St. Louis, was established in 1699 by the French. It was the first permanent settlement in the area. When the French and Indian Wars came to a close, which was in 1763, Great Britain controlled the region. The Indian wars and the Revolutionary War had a major impact on the region throughout the early part of the 1800s.

The Illinois Territory was organized on March 1, 1809. The State of Illinois was created as the 21st state on December 3, 1818.

It has 102 Counties. Illinois borders IndianaKentuckyMissouriIowa and Wisconsin.

List of Illinois Counties

Illinois is divided into 102 counties.

List of Old Former / Extinct Illinois Counties

Illinois has counties that no longer are in existence. A lot of these counties were established and disbanded within the 19th century; county borders have modified very little since 1900 in the vast most of states.

The below Illinois counties no longer exist:

?? County, Illinois

Created ? from ?. It was abolished ? and re-established as ? County on ?.

  • Dane County: Formed in 1839 from MontgomerySangamon and Shelby Counties, renamed in 1840 to Christian County
  • Hignland County: Formed in 1847 from Adams and Marquette Counties, abolished in 1848
  • Marquette County: Formed in 1843 from Adams County, abolished in 1847
  • Wayne County: Formed in 1803 from Knox and St. Clair Counties, abolished in 1847

Map of Illinois County Boundary Changes from 1790 to 1869

This Interactive Map of Illinois Counties show the historical boundaries, names, organization, and attachments of every county, extinct county and unsuccessful county proposal from the creation of Illinois in 1790-1869.

Fun Facts about Illinois Counties

County Name Facts

The County names:

  • 0 of them named for Native American words or people,
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Counties by Year

St. Clair County was the first county created in 1790. The last counties to be formed was Douglas County and Ford County in 1859.

  • ? County was the first county created on ?.
  •  The last county to be formed was ? County on ?.
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Facts for County Size

  • ? County (000 sq mi) is the largest county in Illinois.
  • ? County (000 sq mi) is the smallest county in Illinois.

Facts for County Population (2017 Est.)

  • ? County (000) is the most populated county in Illinois.
  • ? County (000) is the least populated county in Illinois.

Facts for Illinois Counties and Cities

Illinois’s 10 largest cities (2010) are:

  1. Birmingham (000) is in ? County and ? Counties
  2. Chicago, Aurora, Rockford, Joliet, Naperville, Springfield, Peoria, Elgin, Waukegan and Cicero