The 2004 United States presidential election in Pennsylvania took place on November 2, 2004, and was part of the 2004 United States presidential election. Voters chose 21 representatives, or electors to the Electoral College, who voted for president and vice president.

Philadelphia County is the most populous county in Pennsylvania and the 24th-most populous county in the nation. As of the 2020 census, the county had a population of 1,603,797. Its county seat is Philadelphia, the nation's sixth-largest city. The county is part of the Southeast Pennsylvania region of the state.