Illinois Counties
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Illinois Counties

There are one hundred and two counties in Illinois. St. Clair County was the first county established in what is today Illinois. Most counties in Illinois were named after early American leaders, especially of the American Revolutionary War, as well as soldiers from the Battle of Tippecanoe and the War of 1812.

Marion County, Illinois

Marion County Education, Geography, and HistoryMarion County, Illinois Courthouse

Marion County is a county located in the state of Illinois. According to the 2010 census, it had a population of 39,437. Marion County was created on January 24, 1823. The county seat is Salem. The county is named for Francis Marion (1732-1795), general in the American Revolutionary War known as "The Swamp Fox".

Marion County comprises the Centralia, IL Micropolitan Statistical Area, which is included in the St. Louis-St. Charles-Farmington, MO-IL Combined Statistical Area.

Etymology - Origin of Marion County Name

The county is named for General Francis Marion, known as the "Swamp Fox," distinguished soldier in the Carolinas during the American Revolution.


County QuickFacts: CensusBureau Quick Facts

Marion County History

Marion County was created on January 24, 1823 (Laws, 1823, p. 49) and was formed from Fayette and Jefferson Counties. Present area, or parts of it, formerly included in: Jefferson County (1819-1823), Fayette County (1821-1823), Crawford County (1816-1821), Edwards County (1815-1819), Gallatin County (1812-1815), Madison County (1812-1815), Randolph County (1803-1813), St. Clair County (1790-1813) and Knox, Northwest Territory (1790-1801).

The County was named for Francis Marion, a soldier of the Revolution who distinguished himself as a partisan commander in the Carolinas. The County Seat is Salem (1823-Present).

Geography: Land and Water

As reported by the Census Bureau, the county has a total area of 576 square miles (1,491 km2), of which, 572 square miles (1,482 km2) of it is land and 3 square miles (9 km2) of it (0.60%) is water.

Marion county is located in south Illinois. The southwest corner of Marion County is the intersection of the Baseline with the Third Principal Meridian, the point of origin for the third survey of the Northwest Territory under the Land Ordinance of 1785. The origin is marked with a boulder south of Centralia just off US 51.  Stephen A. Forbes State Recreation Area is located in this county.

Neighboring Counties

Bordering counties are as follows:

  • North: Fayette County
  • Northeast: Clay County
  • Southeast: Wayne County
  • South: Jefferson County
  • Southwest: Washington County
  • West: Clinton County


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