Union County /

Union County is a county located in the U.S. state of Illinois. As of the 2000 census, the population was 18,293. Its county seat is Jonesboro, Illinois. According to the 2000 census, the county has a total area of 422.13 square miles (1,093.3 km), of which 416.16 square miles (1,077.8 km) (or 98.59%) is land and 5.97 square miles (15.5 km) (or 1.41%) is water. Union County was formed out of Johnson County in 1818, the same year Illinois joined the Union. As of the census of 2000, there were 18,293 people, 7,290 households, and 4,971 families residing in the county. The population density was 44 people per square mile (17/km²). There were 7,894 housing units at an average density of 19 per square mile (7/km²). The racial makeup of the county was 96.28% White, 0.82% Black or African American, 0.37% Native American, 0.28% Asian, 0.02% Pacific Islander, 1.19% from other races, and 1.04% from two or more races. 2.63% of the population were Hispanic or Latino of any race. 23.7% were of German, 22.7% American, 11.8% English and 10.3% Irish ancestry according to Census 2000. There were 7,290 households out of which 30.30% had children under the age of 18 living with them, 55.60% were