As of the census of 2000, there were 18,723 people, 7,337 households, and 5,091 families residing in the county. The population density was 23 people per square mile (9/km²). There were 8,287 housing units at an average density of 10 per square mile (4/km²). The racial makeup of the county was 70.30% White, 27.16% Black or African American, 0.25% Native American, 0.42% Asian, 0.02% Pacific Islander, 1.00% from other races, and 0.85% from two or more races. 1.76% of the population were Hispanic or Latino of any race.
There were 7,337 households out of which 33.50% had children under the age of 18 living with them, 51.30% were married couples living together, 14.20% had a female householder with no husband present, and 30.60% were non-families. 26.00% of all households are made and 10.50% had someone living alone who was 65 years of age or older. The average household size was 2.46 and the average family size was 2.97.
In the county the population was spread out with 25.80% under the age of 18, 12.60% from 18 to 24, 27.20% from 25 to 44, 21.50% from 45 to 64, and 12.80% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 94.10 males. For every 100 females age 18 and over, there were 91.50 males.
The median income for a household in the county was $28,627, and the median income for a family was $37,317. Males had a median income of $30,794 versus $20,707 for females. The per capita income for the county was $16,264. About 13.10% of families and 18.20% of the population were below the poverty line, including 21.90% of those under age 18 and 21.80% of those age 65 or over.