Marion County, Illinois

In recent years, average temperatures in the county seat of Salem have ranged from a low of 18 °F (−8 °C) in January to a high of 88 °F (31 °C) in July, although a record low of −23 °F (−31 °C) was recorded in January 1994 and a record high of 105 °F (41 °C) was recorded in August 1983. Average monthly precipitation ranged from 2.46 inches (62 mm) in January to 4.37 inches (111 mm) in May.^[5]

• South Central Transit

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

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

As of the 2020 census, the county had a population of 37,729. The median age was 42.7 years, with 22.7% of residents under the age of 18 and 21.2% aged 65 or older. For every 100 females there were 96.2 males, and for every 100 females age 18 and over there were 93.1 males age 18 and over.^[12]

52.2% of residents lived in urban areas, while 47.8% lived in rural areas.^[13]

There were 15,620 households in the county, of which 28.0% had children under the age of 18 living in them. Of all households, 44.8% were married-couple households, 19.2% were households with a male householder and no spouse or partner present, and 28.2% were households with a female householder and no spouse or partner present. About 30.7% of all households were made up of individuals and 15.4% had someone living alone who was 65 years of age or older.^[12]

There were 17,358 housing units, of which 10.0% were vacant. Among occupied housing units, 73.7% were owner-occupied and 26.3% were renter-occupied. The homeowner vacancy rate was 1.6% and the rental vacancy rate was 9.1%.^[12]

As of the 2010 United States census, there were 39,437 people, 16,148 households, and 10,746 families residing in the county.^[23] The population density was 68.9 inhabitants per square mile (26.6/km²). There were 18,296 housing units at an average density of 32.0 per square mile (12.4/km²).^[4] 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.^[23] In terms of ancestry, 27.5% were German, 15.8% were Irish, 13.6% were English, and 10.8% were American.^[24]

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.^[23]

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.^[25]

• Centralia
• Kinmundy
• Salem
• Wamac

Marion County is divided into seventeen townships:

• Greendale
• Tonti