There were 2,108 households out of which 29.10% had children under the age of 18 living with them, 55.30% were married couples living together, 6.80% had a female householder with no husband present, and 34.50% were non-families. 30.80% of all households were made up of individuals and 13.90% had someone living alone who was 65 years of age or older. The average household size was 2.36 and the average family size was 2.96.
In the county the population was spread out with 17.80% under the age of 18, 12.60% from 18 to 24, 37.50% from 25 to 44, 19.40% from 45 to 64, and 12.70% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 174.70 males. For every 100 females age 18 and over, there were 194.50 males.
The median income for a household in the county was $35,445, and the median income for a family was $43,207. Males had a median income of $24,888 versus $20,558 for females. The per capita income for the county was $14,629. About 4.80% of families and 8.50% of the population were below the poverty line, including 10.00% of those under age 18 and 10.00% of those age 65 or over.
The Illinois state prison, Western Illinois Correctional Center, located south east of Mount Sterling, has an average daily population of 2,066. The all male population and racial makeup of the prison is so large, compared to the rest of the county, that it skews the census demographic data. This is evidenced by the lopsided age pyramid.