In 1771 parts of Cumberland County, Johnston County, and Orange County were combined to form Wake County. In July 1784 the western part of Cumberland County became Moore County; the eastern part became Fayette County in honor of the Marquis de la Fayette, but the name Cumberland County was restored three months later. In 1855 the northern part of Cumberland County became Harnett County. Finally, in 1911 parts of Cumberland County and Robeson County were combined to form Hoke County.
By 2005 Cumberland County's population was 51.5% non-Hispanic whites. It was 36.7% African-American. 6.4% of the population was Latino. 3.1% of the population reported more than one race. 2.1% of the population was Asian. 1.7% of the population was Native American.
There were 107,358 households out of which 39.40% had children under the age of 18 living with them, 52.90% were married couples living together, 15.50% had a female householder with no husband present, and 27.70% were non-families. 22.40% of all households were made up of individuals and 5.90% had someone living alone who was 65 years of age or older. The average household size was 2.65 and the average family size was 3.11.
In the county the population was spread out with 27.90% under the age of 18, 13.70% from 18 to 24, 32.90% from 25 to 44, 17.80% from 45 to 64, and 7.70% who were 65 years of age or older. The median age was 30 years. For every 100 females there were 102.30 males. For every 100 females age 18 and over, there were 101.90 males.
The median income for a household in the county was $37,466, and the median income for a family was $41,459. Males had a median income of $28,308 versus $22,379 for females. The per capita income for the county was $17,376. About 10.40% of families and 12.80% of the population were below the poverty line, including 16.80% of those under age 18 and 13.70% of those age 65 or over.
The Cumberland County School system is the fourth largest public school system in the state of North Carolina. There are 11 high schools in Cumberland County: Cape Fear, Douglas Byrd, E.E. Smith, Gray's Creek, Jack Britt, Massey Hill Classical, Pine Forest, Reid Ross Classical, Seventy-First, South View, Terry Sanford, and Westover.