Adjacent counties

• Coshocton County (north)
• Guernsey County (east)
• Noble County (southeast)
• Morgan County (south)
• Perry County (southwest)
• Licking County (west)

2000 census

As of the census^[17] of 2000, there were 84,585 people, 32,518 households, and 22,860 families living in the county. The population density was 127 inhabitants per square mile (49/km²). There were 35,163 housing units at an average density of 53 units per square mile (20/km²). The racial makeup of the county was 93.91% White, 4.01% Black or African American, 0.21% Native American, 0.27% Asian, 0.02% Pacific Islander, 0.20% from other races, and 1.37% from two or more races. 0.52% of the population were Hispanic or Latino of any race.

There were 32,518 households, out of which 33.30% had children under the age of 18 living with them, 54.30% were married couples living together, 12.00% had a female householder with no husband present, and 29.70% were non-families. 24.90% of all households were made up of individuals, and 10.90% had someone living alone who was 65 years of age or older. The average household size was 2.53 and the average family size was 3.01.

In the county, the population was spread out, with 25.90% under the age of 18, 9.40% from 18 to 24, 27.70% from 25 to 44, 22.60% from 45 to 64, and 14.30% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 92.00 males. For every 100 females age 18 and over, there were 88.40 males.

The median income for a household in the county was $35,185, and the median income for a family was $41,938. Males had a median income of $31,537 versus $22,151 for females. The per capita income for the county was $17,533. About 9.90% of families and 12.90% of the population were below the poverty line, including 17.90% of those under age 18 and 10.00% of those age 65 or over.

2010 census

As of the 2010 United States Census, there were 86,074 people, 34,271 households, and 23,125 families living in the county.^[18] The population density was 129.5 inhabitants per square mile (50.0/km²). There were 38,074 housing units at an average density of 57.3 units per square mile (22.1 units/km²).^[19] The racial makeup of the county was 93.0% white, 3.8% black or African American, 0.3% Asian, 0.2% American Indian, 0.2% from other races, and 2.5% from two or more races. Those of Hispanic or Latino origin made up 0.8% of the population.^[18] In terms of ancestry, 25.2% were German, 15.5% were Irish, 11.1% were American, and 10.9% were English.^[20]

Of the 34,271 households, 32.3% had children under the age of 18 living with them, 49.1% were married couples living together, 13.2% had a female householder with no husband present, 32.5% were non-families, and 26.9% of all households were made up of individuals. The average household size was 2.46 and the average family size was 2.95. The median age was 39.5 years.^[18]

The median income for a household in the county was $39,538 and the median income for a family was $48,425. Males had a median income of $40,183 versus $28,668 for females. The per capita income for the county was $20,561. About 13.0% of families and 16.6% of the population were below the poverty line, including 24.6% of those under age 18 and 9.3% of those age 65 or over.^[21]

City

• Zanesville (county seat)

Villages

Townships

Census-designated places

• Duncan Falls
• East Fultonham
• North Zanesville
• Pleasant Grove
• Trinway

Other unincorporated communities

Historical places

• Irville - Former populated place in Licking Township, removed for the creation of Dillon Lake.
• Mattingly Settlement - Named for the many members of the Mattingly family who settled in Muskingum Township.