Cooper County is a county located in the central portion of the U.S. state of Missouri. As of the 2010 census, the population was 17,601. Its county seat is Boonville. The county was organized December 17, 1818 and named for Sarshell Cooper, a frontier settler who was killed by Native Americans near Arrow Rock in 1814. It is a part of the Columbia, Missouri metropolitan area.
According to the U.S. Census Bureau, the county has a total area of 569 square miles (1,470 km), of which 565 square miles (1,460 km) is land and 4.4 square miles (11 km) (0.8%) is water.
As of the 2000 census, there were 16,670 people, 5,932 households and 4,140 families residing in the county. The population density was 30 per square mile (11/km²). There were 6,676 housing units at an average density of 12 per square mile (5/km²). The racial makeup of the county was 89.05% White, 8.96% Black or African American, 0.36% Native American, 0.23% Asian, 0.02% Pacific Islander, 0.28% from other races, and 1.11% from two or more races. Approximately 0.86% of the population were Hispanic or Latino of any race. 38.1% were of German, 18.7% American, 8.1% English and 8.0% Irish ancestry.
There were 5,932 households, of which 31.80% had children under the age of 18 living with them, 57.40% were married couples living together, 9.00% had a female householder with no husband present, and 30.20% were non-families. 26.10% of all households were made up of individuals and 12.60% had someone living alone who was 65 years of age or older. The average household size was 2.46 and the average family size was 2.97.
Age distribution was 22.80% under the age of 18, 14.00% from 18 to 24, 27.40% from 25 to 44, 20.60% from 45 to 64, and 15.20% who were 65 years of age or older. The median age was 35 years. For every 100 females, there were 117.40 males. For every 100 females age 18 and over, there were 120.00 males.
The median household income was $35,313, and the median family income was $41,526. Males had a median income of $28,513 versus $20,965 for females. The per capita income for the county was $15,648. About 8.30% of families and 10.70% of the population were below the poverty line, including 12.80% of those under age 18 and 8.30% of those age 65 or over.