William Stewart (September 10, 1810 - October 17, 1876) was an American lawyer and Republican member of the U.S. House of Representatives from Pennsylvania.
Born in Mercer, Pennsylvania on September 10, 1810, William Stewart attended the public schools of his community before graduating from Jefferson College in Canonsburg, Pennsylvania.
Stewart went on to study law, was admitted to the bar and began his legal practice in Mercer.
A member of the Pennsylvania State Senate, he was subsequently elected as a Republican to the Thirty-fifth and Thirty-sixth Congresses, and was appointed as chair of the United States House Committee on Expenditures in the Department of War during the Thirty-sixth Congress.
Following his retirement from Congress, he resumed the practice of law.
Stewart died in Mercer in 1876 at the age of sixty-six, and was interred in the Mercer Cemetery.