Marion County is a county located in the U.S. state of Illinois. According to the 2010 census, it had a population of 39,437. Its county seat is Salem. Marion County comprises the Centralia, IL Micropolitan Statistical Area, which is included in the St. Louis-St. Charles-Farmington, MO-IL Combined Statistical Area.


Marion County was organized on 24 January 1823 from portions of Jefferson and Fayette counties. It was named in honor of Revolutionary War Gen. Francis Marion, the "Swamp Fox". File:Marion County Illinois 1823.png|Marion County at the time of its creation in 1823


According to the U.S. Census Bureau, the county has a total area of , of which is land and (0.6%) is water. 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 U.S. 51.

Climate and weather

In recent years, average temperatures in the county seat of Salem have ranged from a low of in January to a high of in July, although a record low of was recorded in January 1994 and a record high of was recorded in August 1983. Average monthly precipitation ranged from in January to in May.

Major highways

* Interstate 57 * U.S. Route 50 * U.S. Route 51 * Illinois Route 37 * Illinois Route 161

Adjacent counties

* Fayette County - north * Clay County - east * Wayne County - southeast * Jefferson County - south * Washington County - southwest * Clinton County - west


As of the 2010 United States Census, there were 39,437 people, 16,148 households, and 10,746 families residing in the county. The population density was . There were 18,296 housing units at an average density of . The racial makeup of the county was 93.1% white, 3.9% black or African American, 0.6% Asian, 0.3% American Indian, 0.4% from other races, and 1.6% from two or more races. Those of Hispanic or Latino origin made up 1.4% of the population. In terms of ancestry, 27.5% were German, 15.8% were Irish, 13.6% were English, and 10.8% were American. Of the 16,148 households, 30.9% had children under the age of 18 living with them, 48.9% were married couples living together, 12.8% had a female householder with no husband present, 33.5% were non-families, and 28.8% of all households were made up of individuals. The average household size was 2.40 and the average family size was 2.91. The median age was 41.4 years. The median income for a household in the county was $38,974 and the median income for a family was $50,518. Males had a median income of $41,428 versus $28,042 for females. The per capita income for the county was $20,493. About 12.2% of families and 16.5% of the population were below the poverty line, including 23.9% of those under age 18 and 9.6% of those age 65 or over.



* Centralia * Kinmundy * Salem * Wamac


* Alma * Central City * Iuka * Junction City * Kell * Odin * Patoka * Sandoval * Vernon * Walnut Hill

Census-designated places

* Cartter * Fairman * Finney Heights * Glen Ridge * Helm * Slap Out * Suburban


Marion County is divided into seventeen townships: * Alma * Carrigan * Centralia * Foster * Haines * Iuka * Kinmundy * Meacham * Odin * Omega * Patoka * Raccoon * Romine * Salem * Sandoval * Stevenson * Tonti


Initially a strongly Democratic anti-Yankee county, Marion County has undergone two transitions. Between 1912 and 2004 it was a perfect bellwether apart from the Catholicism-influenced 1960 election when substantial anti-Catholic voting by its largely southern white population caused it to support Republican Richard Nixon. Since the beginning of the twenty-first century, strong opposition to the Democratic Party's liberal views on social issues has transformed the county into a powerfully Republican one,Cohn, Nate
‘Demographic Shift: Southern Whites’ Loyalty to G.O.P. Nearing That of Blacks to Democrats’
, ''New York Times'', April 24, 2014
with Hillary Clinton receiving a vote share over twelve percent smaller than any pre-2010 Democratic presidential nominee.

See also

* National Register of Historic Places listings in Marion County, Illinois


{{Coord|38.65|-88.92|display=title|type:adm2nd_region:US-IL_source:UScensus1990 Category:Illinois counties Category:1823 establishments in Illinois Category:Populated places established in 1823 Marion County, Illinois