Christian County is part of the Clarksville, TN–KY Metropolitan Statistical Area.
As of the census of 2000, there were 72,265 people, 24,857 households, and 18,344 families residing in the county. The population density was 100 per square mile (39 /km). There were 27,182 housing units at an average density of 38 per square mile (15 /km). The racial makeup of the county was 69.92% White, 23.73% Black or African American, 0.52% Native American, 0.91% Asian, 0.32% Pacific Islander, 2.23% from other races, and 2.37% from two or more races. 4.83% of the population were Hispanic or Latino of any race. This number, however, was estimated to be around 4% for a 2006 Census Estimate, according to the United States Census Bureau.
There were 24,857 households out of which 41.10% had children under the age of 18 living with them, 57.00% were married couples living together, 13.60% had a female householder with no husband present, and 26.20% were non-families. 22.50% 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 2.66 and the average family size was 3.12.
In the county the population was spread out with 28.30% under the age of 18, 15.80% from 18 to 24, 30.10% from 25 to 44, 16.00% from 45 to 64, and 9.80% who were 65 years of age or older. The median age was 28 years. For every 100 females there were 106.60 males. For every 100 females age 18 and over, there were 107.60 males.
The median income for a household in the county was $31,177, and the median income for a family was $35,240. Males had a median income of $25,063 versus $20,748 for females. The per capita income for the county was $14,611. About 12.10% of families and 15.00% of the population were below the poverty line, including 19.30% of those under age 18 and 13.50% of those age 65 or over.