|Elections in Pennsylvania|
The Republican Simon Cameron was elected to the United States Senate by the General Assembly, consisting of the House of Representatives and the Senate, in January 1857. Sen. Cameron resigned on March 4, 1861, to become United States Secretary of War in the Abraham Lincoln administration, vacating the seat.
Following the resignation of Sen. Simon Cameron, the Pennsylvania General Assembly convened on March 14, 1861, to elect a new Senator to fill the vacancy. The results of the vote of both houses combined are as follows:
|Democratic||William H. Welsh||34||25.56|
|Republican||Winthrop W. Ketcham||1||0.75|
| Pennsylvania U.S. Senate election (Class I)