Hamilton County is a county located in the U.S. state of Illinois. According to the 2010 census, it has a population of 8,457. Its county seat is McLeansboro. It is located in the southern portion of the state known locally as “Little Egypt”.
According to the U.S. Census Bureau, the county has a total area of 436 square miles (1,130 km), of which 435 square miles (1,130 km) is land and 1.2 square miles (3.1 km) (0.3%) is water.
As of the 2010 United States Census, there were 8,457 people, 3,489 households, and 2,376 families residing in the county. The population density was 19.5 inhabitants per square mile (7.5/km). There were 4,104 housing units at an average density of 9.4 per square mile (3.6/km). The racial makeup of the county was 98.2% white, 0.4% black or African American, 0.2% Asian, 0.2% American Indian, 0.3% from other races, and 0.7% from two or more races. Those of Hispanic or Latino origin made up 1.2% of the population. In terms of ancestry, 33.1% were German, 20.7% were Irish, 11.4% were English, and 10.3% were American.
Of the 3,489 households, 29.8% had children under the age of 18 living with them, 54.9% were married couples living together, 9.2% had a female householder with no husband present, 31.9% were non-families, and 28.1% of all households were made up of individuals. The average household size was 2.39 and the average family size was 2.91. The median age was 43.1 years.
The median income for a household in the county was $35,032 and the median income for a family was $50,878. Males had a median income of $45,245 versus $23,491 for females. The per capita income for the county was $21,602. About 8.2% of families and 14.5% of the population were below the poverty line, including 21.5% of those under age 18 and 8.5% of those age 65 or over.