Adjacent counties

• Richland County (north)
• Ashland County (far northeast)
• Holmes County (northeast)
• Coshocton County (east)
• Licking County (south)
• Delaware County (southwest)
• Morrow County (northwest)

2000 census

As of the census^[12] of 2010,^[13] 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 99.4 males.^[14]

The median income for a household in the county was $48,734, and the median income for a family was $50,034. The per capita income for the county was $22,628. About 9.4% of families and 13.0% of the population were below the poverty line, including 19.2% of those under age 18 and 8.3% of those age 65 or over.

In Knox county, the 2000 census reported that the number of same-sex couples was 91 and the percent of same-sex couples out of all households was 0.46%.^[15]

2010 census

As of the 2010 United States Census, there were 60,921 people, 22,607 households, and 15,693 families living in the county.^[16] The population density was 115.9 inhabitants per square mile (44.7/km²). There were 25,118 housing units at an average density of 47.8 per square mile (18.5/km²).^[17] The racial makeup of the county was 96.7% white, 0.8% black or African American, 0.6% Asian, 0.2% American Indian, 0.4% from other races, and 1.2% from two or more races. Those of Hispanic or Latino origin made up 1.2% of the population.^[16] In terms of ancestry, 30.5% were German, 14.4% were Irish, 13.9% were English, and 9.2% were American.^[18]

Of the 22,607 households, 32.4% 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, 30.6% were non-families, and 25.7% of all households were made up of individuals. The average household size was 2.54 and the average family size was 3.04. The median age was 38.3 years.^[16]

The median income for a household in the county was $45,655 and the median income for a family was $55,881. Males had a median income of $41,762 versus $30,836 for females. The per capita income for the county was $21,204. About 9.1% of families and 13.1% of the population were below the poverty line, including 18.8% of those under age 18 and 9.5% of those age 65 or over.^[19]

County Commissioners

• Theresa Bemiller, Republican
• Bill Pursel, Republican
• Thom Collier, Republican

State Senate

• Andrew Brenner, Republican, Ohio's 19th Senatorial District

State representative

• Rick Carfagna, Republican, Ohio's 68th Representative District

United States House of Representatives

• Troy Balderson, Republican, Ohio's 12th congressional district

United States Senators

• Sherrod Brown, Democrat, Ohio
• J. D. Vance, Republican, Ohio

City

• Mount Vernon (county seat)

Villages

• Centerburg
• Danville
• Fredericktown
• Gambier
• Gann
• Martinsburg
• Utica

Townships

Census-designated places

• Apple Valley
• Bladensburg
• Howard
• South Mount Vernon

Unincorporated communities