As of the 2000 United States Census there were 508,932 people, 185,744 households, and 129,835 families residing in the county. The population density was 2,289 people per square mile (884/km2). There were 199,679 housing units at an average density of 898 per square mile (347/km2). The racial makeup of the county was 70.88% White American, 18.09% Black or African American, 0.26% Native American, 3.72% Asian, 0.04% Pacific Islander, 5.09% from other races, and 1.93% from two or more races. 9.66% of the population were Hispanic or Latino of any race. Among those residents listing their ancestry, 20.6% of residents were of Irish, 18.2% Italian, 15.7% German and 8.1% English ancestry.