Harrison County is a county located in the northwest portion of the U.S. state of Missouri. As of the 2010 census, the population was 8,957. Its county seat is Bethany. The county was organized February 14, 1845 and named for U.S. Representative Albert G. Harrison of Missouri.
According to the U.S. Census Bureau, the county has a total area of 726 square miles (1,880 km), of which 723 square miles (1,870 km) is land and 3.9 square miles (10 km) (0.5%) is water.
As of the 2010 census, there were 8,957 people, 3,669 households and 2,461 families residing in the county. The population density was 12 people per square mile (5/km²). There were 4,407 housing units at an average density of 6 per square mile (2/km²). The racial makeup of the county was 97.55% White, 0.36% Native American, 0.33% Black or African American, 0.20% Asian, 0.10% Pacific Islander, 0.52% from other races and 0.93% from two or more races. Approximately 1.57% of the population were Hispanic or Latino of any race.
There were 3,669 households out of which 29.79% had children under the age of 18 living with them, 54.51% were married couples living together, 8.29% had a female householder with no husband present and 32.92% were non-families. 28.26% of all households were made up of individuals and 14.31% had someone living alone who was 65 years of age or older. The average household size was 2.40 and the average family size was 2.93.
In the county, the population was spread out with 24.80% under the age of 18, 7.18% from 18 to 24, 20.88% from 25 to 44, 26.44% from 45 to 64 and 20.70% who were 65 years of age or older. The median age was 42.6 years. For every 100 females there were 98.47 males. For every 100 females age 18 and over, there were 93.79 males.
The median income for a household in the county was $35,000 and the median income for a family was $47,788. Males had a median income of $33,105 versus $25,388 for females. The per capita income for the county was $18,967. About 10.3% of families and 15.1% of the population were below the poverty line, including 18.9% of those under age 18 and 13.8% of those age 65 or over.
According to the Association of Religion Data Archives County Membership Report (2010), evangelical Protestantism is the most common religion among adherents in Harrison County, although 37.69% of the population does not claim any religion. The most predominant denominations among residents in Harrison County who adhere to a religion are Southern Baptists (44.11%), United Methodists (10.77%) and Disciples of Christ (10.76%).