Union County was formed out ofJohnson County, nearly a year before theIllinois Territory gained statehood.[4] It was named for a joint revival meeting of theBaptists andDunkards, called a "union meeting". The county seal depicts the leaders of these two groups shaking hands.[5]
For its first year of existence, Union County included an area of unorganized territory temporarily attached to it.[6]
In 1819, the additional territory became Alexander County, reducing Union to its current borders.
According to theUS Census Bureau, the county has a total area of 422 square miles (1,090 km2), of which 413 square miles (1,070 km2) is land and 8.7 square miles (23 km2) (2.1%) is water.[7]
In recent years, average temperatures in the county seat of Jonesboro have ranged from a low of 22 °F (−6 °C) in January to a high of 90 °F (32 °C) in July, although a record low of −20 °F (−29 °C) was recorded in January 1918 and a record high of 112 °F (44 °C) was recorded in July 1901. Average monthly precipitation ranged from 3.13 inches (80 mm) in September to 5.22 inches (133 mm) in May.[8]
As of the2020 census, the county had a population of 17,244. The median age was 44.9 years. 20.4% of residents were under the age of 18 and 22.3% of residents were 65 years of age or older. For every 100 females there were 101.0 males, and for every 100 females age 18 and over there were 100.7 males age 18 and over.[18][19]
35.2% of residents lived in urban areas, while 64.8% lived in rural areas.[20]
There were 6,983 households in the county, of which 27.4% had children under the age of 18 living in them. Of all households, 47.7% were married-couple households, 18.0% were households with a male householder and no spouse or partner present, and 27.5% were households with a female householder and no spouse or partner present. About 30.8% of all households were made up of individuals and 15.6% had someone living alone who was 65 years of age or older.[18]
There were 7,841 housing units, of which 10.9% were vacant. Among occupied housing units, 74.7% were owner-occupied and 25.3% were renter-occupied. The homeowner vacancy rate was 2.2% and the rental vacancy rate was 11.3%.[18]
Union County, Illinois – Racial and ethnic composition Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos may be of any race.
As of the2010 United States census, there were 17,808 people, 7,167 households, and 4,837 families residing in the county.[30] The population density was 43.1 inhabitants per square mile (16.6/km2). There were 7,924 housing units at an average density of 19.2 per square mile (7.4/km2).[7] The racial makeup of the county was 94.8% white, 0.9% black or African American, 0.5% American Indian, 0.3% Asian, 2.0% from other races, and 1.5% from two or more races. Those of Hispanic or Latino origin made up 4.8% of the population.[30] In terms of ancestry, 23.0% wereGerman, 12.6% wereIrish, 9.4% wereEnglish, and 8.1% wereAmerican.[31]
Of the 7,167 households, 29.7% had children under the age of 18 living with them, 52.6% were married couples living together, 10.6% had a female householder with no husband present, 32.5% were non-families, and 28.4% of all households were made up of individuals. The average household size was 2.41 and the average family size was 2.92. The median age was 42.9 years.[30]
The median income for a household in the county was $39,760 and the median income for a family was $48,465. Males had a median income of $36,831 versus $31,272 for females. The per capita income for the county was $19,512. About 12.7% of families and 21.1% of the population were below thepoverty line, including 22.5% of those under age 18 and 16.7% of those age 65 or over.[32]
Like much ofSouthern Illinois, Union County has shifted toward the Republican Party over the past couple decades,[33] with the Republican candidate for president winning the county since 2000.
United States presidential election results for Union County, Illinois[34]