Franklin County is a county located in the U.S. state of Illinois. According to the 2010 census, it has a population of 39,561. Its county seat is Benton. It is located in the southern portion of Illinois known locally as “Little Egypt”.
According to the U.S. Census Bureau, the county has a total area of 431 square miles (1,120 km), of which 409 square miles (1,060 km) is land and 23 square miles (60 km) (5.2%) is water. Justin Kay State Recreation Area is located in this county.
As of the 2010 United States Census, there were 39,561 people, 16,617 households, and 10,912 families residing in the county. The population density was 96.8 inhabitants per square mile (37.4/km). There were 18,525 housing units at an average density of 45.3 per square mile (17.5/km). The racial makeup of the county was 97.7% white, 0.3% Asian, 0.3% American Indian, 0.3% black or African American, 0.3% from other races, and 1.1% from two or more races. Those of Hispanic or Latino origin made up 1.2% of the population. In terms of ancestry, 21.8% were German, 18.7% were Irish, 15.9% were English, 9.4% were American, and 5.7% were Italian.
Of the 16,617 households, 30.0% had children under the age of 18 living with them, 48.8% were married couples living together, 11.6% had a female householder with no husband present, 34.3% were non-families, and 30.0% of all households were made up of individuals. The average household size was 2.35 and the average family size was 2.88. The median age was 41.8 years.
The median income for a household in the county was $34,381 and the median income for a family was $43,170. Males had a median income of $39,122 versus $28,950 for females. The per capita income for the county was $18,504. About 14.5% of families and 19.8% of the population were below the poverty line, including 30.5% of those under age 18 and 9.9% of those age 65 or over.