Knox County, Ohio  Knox County is a county located in the U.S. state of Ohio. As of the 2010 census, the population was 60,921. Its county seat is Mount Vernon. The county is named for Henry Knox, an officer in the American Revolutionary War who was later the first Secretary of War. Knox County comprises the Mount Vernon, OH Micropolitan Statistical Area, which is also included in the Columbus-Marion-Zanesville, OH Combined Statistical Area. Knox County was formed from Fairfield County in 1808. A rich African American cultural heritage has existed in the county since its founding. According to the U.S. Census Bureau, the county has a total area of , of which is land and (0.8%) is water. Approximately 58% of the county is farmland and 28% is forested. Most of the county lies in the Glaciated Allegheny Plateau with rolling hills and valleys. Although the relief is not sharp, some elevations in the county reach over 1400 feet above sea level. As of the census of 2010, there were 60,921 people, 22,607 households, and 15,693 families living in the county. There were 24,997 housing units. The racial makeup of the county was 96.7% White, 0.8% Black or African American, 0.2% Native American, 0.6% Asian, 0.03% Pacific Islander, 0.4% from other races, and 1.2% from two or more races. 1.2% of the population were Hispanic or Latino of any race. There were 22,607 households out of which 29.5% had children under the age of 18 living with them, 55.2% were married couples living together, 9.7% had a female householder with no husband present, and 30.6% were non-families. 25.7% of all households were made up of individuals and 27.4% had someone living alone who was 65 years of age or older. The average household size was 2.54 and the average family size was 3.04. In the county, the population was spread out with 28.0% under the age of 20, 7.9% from 20 to 24, 22.5% from 25 to 44, 27.0% from 45 to 64, and 14.8% who were 65 years of age or older. The median age was 38.3 years. For every 100 females there were 94.70 males.