Clinton extends Democratic presidential contest with victory in Pennsylvania primary

The demographic and geographic split among Democratic primary voters was substantial. Obama won 90 percent of the votes cast by African-Americans, while Clinton won 67 percent of those cast by white voters. Clinton won sizeable majorities among voters with incomes under $50,000 a year and among voters in small towns and rural areas.

Obama took a large majority of the votes of those under 30, while Clinton took even greater margins among the elderly, who constituted a much larger share of the vote in Pennsylvania than in most other primary states. Young voters were only 12 percent of those participating, while 22 percent were over 65.

Obama carried only seven of the states 67 counties, including Philadelphia and two of its suburban counties, as well as Lancaster, Dauphin (Harrisburg) and two counties around State College, where Penn State University is located. Obama had 63 percent of the vote in Philadelphia, the most populous county, but Clinton carried Allegheny County, the second largest, which includes Pittsburgh, with 54 percent.