William Thompson (July 5, 1736 – September 3, 1781) was a soldier from Pennsylvania who served as a colonel and later brigadier general in the Continental Army during the American Revolutionary War.
Thompson was born in Ireland and emigrated to Carlisle, Pennsylvania. During the French and Indian War, Thompson served as a captain in the Kittanning Expedition under John Armstrong.
After news of the Battle of Bunker Hill reached Pennsylvania in 1775, Thompson was appointed colonel of a rifle battalion and was sent to Massachusetts to help in the defense of Boston. His unit was known as Thompson's Pennsylvania Rifle Battalion, or the 1st Pennsylvania Regiment. After Thompson's company of Pennsylvania sharpshooters drove back a British landing-party on November 9, 1775, he was made a brigadier-general, to the displeasure of George Washington, who had reservations about Thompson's abilities.
Sent to reinforce American troops in Canada, Thompson was captured during an attack on the enemy at Trois-Rivières in Quebec on June 8, 1776. He was paroled, but not exchanged for four years, and so he could not reenter military service. Thompson blamed Congressman Thomas McKean for hindering his exchange; his criticism became so harsh that he was censured by Congress. McKean successfully sued Thompson for libel.
Thompson married Katherine Ross daughter of George Ross, signer of the Declaration of Independence for Pennsylvania.
While on parole in Philadelphia on December 17, 1778 he became an early Member of the Friendly Sons of St. Patrick