Pike County is a county in the U.S. state of Illinois. According to the 2010 United States Census, it had a population of 16,430. Its county seat is Pittsfield.
According to the US Census Bureau, the county has a total area of 849 square miles (2,200 km), of which 831 square miles (2,150 km) is land and 18 square miles (47 km) (2.1%) is water.
Pike County is located on the highlands between the Illinois River, which forms its eastern border, and the Mississippi River, which borders Missouri. It has two interstate highways, I-72, with bridges spanning both rivers to enter the county, and I-172 which extends about 300 feet (91 m) into the county to its intersection with I-72.
As of the 2010 United States Census, there were 16,430 people, 6,639 households, and 4,527 families residing in the county. The population density was 19.8 inhabitants per square mile (7.6/km). There were 7,951 housing units at an average density of 9.6 per square mile (3.7/km). The racial makeup of the county was 96.9% white, 1.7% black or African American, 0.2% Asian, 0.2% American Indian, 0.2% from other races, and 0.7% from two or more races. Those of Hispanic or Latino origin made up 1.0% of the population. In terms of ancestry, 26.3% were German, 16.8% were American, 15.1% were English, and 13.4% were Irish.
Of the 6,639 households, 30.3% had children under the age of 18 living with them, 54.5% were married couples living together, 9.0% had a female householder with no husband present, 31.8% were non-families, and 27.8% of all households were made up of individuals. The average household size was 2.38 and the average family size was 2.87. The median age was 42.5 years.
The median income for a household in the county was $40,205 and the median income for a family was $50,426. Males had a median income of $39,071 versus $26,835 for females. The per capita income for the county was $19,996. About 11.3% of families and 15.4% of the population were below the poverty line, including 23.7% of those under age 18 and 11.2% of those age 65 or over.