As of the 2010 census, there were 301,356 people, 116,274 households, and 80,077 families residing in the county. The population density was . There were 127,036 housing units at an average density of . The racial makeup of the county was 84.8% white, 8.6% black or African American, 0.9% Asian, 0.3% American Indian, 2.5% from other races, and 3.0% from two or more races. Those of Hispanic or Latino origin made up 8.4% of the population. In terms of ancestry, 26.5% were German, 16.7% were Irish, 10.9% were English, 8.4% were Polish, 8.2% were Italian, 6.2% were American, and 5.2% were Hungarian.