As of the census of 2006, there were 275,534 people, 97,735 households, and 69,294 families residing in the county. The population density was 313 people per square mile (121/km²). There were 106,986 housing units at an average density of 132 per square mile (51/km²). The racial makeup of the county was 75.09% White, 20.79% Black or African American, 0.22% Native American, 1.47% Asian, 0.03% Pacific Islander, 1.35% from other races, and 1.04% from two or more races. 2.79% of the population were Hispanic or Latino of any race. 24.8% were of American, 9.5% English, 7.9% Irish and 6.9% German ancestry according to Census 2000. 94.7% spoke English and 3.4% Spanish as their first language.
There were 97,735 households out of which 32.20% had children under the age of 18 living with them, 52.80% were married couples living together, 13.80% had a female householder with no husband present, and 29.10% were non-families. 24.80% 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 2.52 and the average family size was 3.01.
In the county, the population was spread out with 24.80% under the age of 18, 9.20% from 18 to 24, 29.90% from 25 to 44, 23.60% from 45 to 64, and 12.50% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 94.50 males. For every 100 females age 18 and over, there were 91.30 males.
The median income for a household in the county was $37,579, and the median income for a family was $45,349. Males had a median income of $33,002 versus $23,911 for females. The per capita income for the county was $18,738. About 9.20% of families and 12.30% of the population were below the poverty line, including 15.00% of those under age 18 and 13.30% of those age 65 or over.