As of the census of 2000, there were 654,880 people, 266,294 households, and 166,167 families residing in the county. The population density was 1,083 people per square mile (418/km2). There were 288,231 housing units at an average density of 476 per square mile (184/km2). The racial makeup of the county was 70.10% White, 23.27% Black or African American, 0.48% Native American, 1.28% Asian, 0.18% Pacific Islander, 2.43% from other races, and 2.25% from two or more races. 5.37% of the population were Hispanic or Latino of any race. 16.7% were of German, 9.1% American, 8.9% Irish and 8.8% English ancestry.