According to the U.S. Census Bureau, the county has a total area of, of which is land and is water. The county is located in the Piedmont region of the state. The western portion of Spalding County, west of a line from Sunny Side through Griffin to Orchard Hill, is located in the Upper Flint River sub-basin of the ACF River Basin. The eastern part of the county is located in the Upper Ocmulgee River sub-basin of the Altamaha River basin.
As of the census of 2000, there were 58,417 people, 21,519 households, and 15,773 families living in the county. The population density was 295 people per square mile. There were 23,001 housing units at an average density of 116 per square mile. The racial makeup of the county was 66.50% White, 31.05% Black or African American, 0.23% Native American, 0.67% Asian, 0.02% Pacific Islander, 0.65% from other races, and 0.88% from two or more races. 1.62% of the population were Hispanic or Latino of any race. There were 21,519 households out of which 34.00% had children under the age of 18 living with them, 50.30% were married couplesliving together, 18.20% had a female householder with no husband present, and 26.70% were non-families. 22.30% of all households were made up of individuals and 8.50% had someone living alone who was 65 years of age or older. The average household size was 2.67 and the average family size was 3.12. In the county, the population was spread out with 27.30% under the age of 18, 9.20% from 18 to 24, 29.40% from 25 to 44, 22.50% from 45 to 64, and 11.70% who were 65 years of age or older. The median age was 35 years. For every 100 females, there were 93.20 males. For every 100 females age 18 and over, there were 88.90 males. The median income for a household in the county was $36,221, and the median income for a family was $41,631. Males had a median income of $32,347 versus $22,114 for females. The per capita income for the county was $16,791. About 12.40% of families and 15.50% of the population were below the poverty line, including 21.30% of those under age 18 and 11.30% of those age 65 or over.
2010 census
As of the 2010 United States Census, there were 64,073 people, 23,565 households, and 16,869 families living in the county. The population density was. There were 26,777 housing units at an average density of. The racial makeup of the county was 62.7% white, 32.8% black or African American, 0.9% Asian, 0.3% American Indian, 0.1% Pacific islander, 1.6% from other races, and 1.6% from two or more races. Those of Hispanic or Latino origin made up 3.8% of the population. In terms of ancestry, 23.3% were American, 7.6% were Irish, and 6.9% were English. Of the 23,565 households, 36.2% had children under the age of 18 living with them, 46.3% were married couples living together, 19.4% had a female householder with no husband present, 28.4% were non-families, and 23.5% of all households were made up of individuals. The average household size was 2.67 and the average family size was 3.12. The median age was 37.2 years. The median income for a household in the county was $41,100 and the median income for a family was $49,640. Males had a median income of $37,976 versus $30,684 for females. The per capita income for the county was $19,607. About 17.2% of families and 21.2% of the population were below the poverty line, including 30.4% of those under age 18 and 14.0% of those age 65 or over.
