According to the U.S. Census Bureau, the county has a total area of, of which is land and is water. It is the fourth-largest county in Georgia by land area and third-largest by total area. Eastern and southeastern portions of the county lie within the Okefenokee Swamp and its federally protected areas. The vast majority of Clinch County is located in the Upper Suwannee River sub-basin of the Suwannee River basin, with just a portion of the western and northwestern edge of the county, southwest and well northwest of Du Pont, located in the Alapaha River sub-basin of the same Suwannee River basin.
As of the census of 2000, there were 6,878 people, 2,512 households, and 1,823 families living in the county. The population density was 8 people per square mile. There were 2,837 housing units at an average density of 4 per square mile. The racial makeup of the county was 68.93% White or European American, 29.50% Black or African American, 0.51% Native American, 0.12% Asian, 0.10% from other races, and 0.84% from two or more races. 0.79% of the population were Hispanic or Latino of any race. As of the census of 2010 there were 6,798 people in Clinch County. 69.7% were White or European American, 27.7% were Black or African American, 0.8% were American Indian or Alaska Native, 0.2% were Asian and 0.1% were Native Hawaiian and other Pacific Islander. There were 2,512 households out of which 36.50% had children under the age of 18 living with them, 51.70% were married couplesliving together, 16.90% had a female householder with no husband present, and 27.40% were non-families. 24.60% of all households were made up of individuals and 9.20% had someone living alone who was 65 years of age or older. The average household size was 2.60 and the average family size was 3.09. In the county, the population was spread out with 27.90% under the age of 18, 8.60% from 18 to 24, 29.00% from 25 to 44, 22.70% from 45 to 64, and 11.80% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 98.90 males. For every 100 females age 18 and over, there were 96.50 males. The median income for a household in the county was $26,755, and the median income for a family was $31,755. Males had a median income of $26,905 versus $19,347 for females. The per capita income for the county was $13,023. About 22.20% of families and 23.40% of the population were below the poverty line, including 26.90% of those under age 18 and 30.90% of those age 65 or over.
2010 census
As of the 2010 United States Census, there were 6,798 people, 2,572 households, and 1,821 families living in the county. The population density was. There were 3,007 housing units at an average density of. The racial makeup of the county was 67.4% white, 27.7% black or African American, 0.6% American Indian, 0.2% Asian, 0.1% Pacific islander, 2.6% from other races, and 1.4% from two or more races. Those of Hispanic or Latino origin made up 3.5% of the population. In terms of ancestry, 11.0% were English, 8.0% were Irish, and 8.0% were American. Of the 2,572 households, 38.4% had children under the age of 18 living with them, 46.5% were married couples living together, 19.4% had a female householder with no husband present, 29.2% were non-families, and 25.7% of all households were made up of individuals. The average household size was 2.58 and the average family size was 3.10. The median age was 36.8 years. The median income for a household in the county was $31,963 and the median income for a family was $45,350. Males had a median income of $31,739 versus $25,972 for females. The per capita income for the county was $16,709. About 19.1% of families and 25.7% of the population were below the poverty line, including 37.7% of those under age 18 and 24.3% of those age 65 or over.
