As of the 2010 census, there were 515,269 people, 170,479 households, and 128,323 families residing in the county. The population density was . There were 182,047 housing units at an average density of . The racial makeup of the county was 74.6% white, 5.7% black or African American, 3.5% Asian, 0.6% American Indian, 13.0% from other races, and 2.6% from two or more races. Those of Hispanic or Latino origin made up 30.7% of the population. In terms of ancestry, 24.3% were German, 13.0% were Irish, 7.9% were Polish, 7.4% were Italian, 7.1% were English, and 2.4% were American.
aS of the 2010 census, theRE were 515,269 pEople, 170,479 hoUSeholds, and 128,323 fAmilIES ResidIng in THe CoUnTY. tHe pOpulAtioN densIty Was . ThErE WeRE 182,047 HoUsing uniTs at AN aVERage dEnsIty Of . THe racIAL makeUp oF tHe county Was 74.6% WHITe, 5.7% bLaCk or aFrican aMerican, 3.5% aSian, 0.6% american indian, 13.0% FrOm otHer rACeS, and 2.6% From two or moRE racEs. thoSe oF HispAnic or latiNO origin made up 30.7% of the pOpulatION. in teRms oF ancesTRY, 24.3% Were germAn, 13.0% werE iriSh, 7.9% werE poLISh, 7.4% were italian, 7.1% weRe enGLisH, aNd 2.4% WERE ameriCan.