The 1824–1825 United States Senate election in Pennsylvania was held between December 1824 and February 1825. William Marks was elected by the Pennsylvania General Assembly to the United States Senate.[1]
Incumbent Democratic-Republican Walter Lowrie, who was elected in 1818, was not a candidate for re-election to another term. The Pennsylvania General Assembly, consisting of the House of Representatives and the Senate, convened on December 14, 1824, to elect a new Senator to fill the term beginning on March 4, 1825. Thirty-two ballots were recorded between that date and February 14, 1825. The results of the thirty-second and final ballot of both houses combined are as follows:
|-|-bgcolor="#EEEEEE"| colspan="3" align="right" | Totals| align="right" | 133| align="right" | 100.00%|}