John Whistler (ca. 1756 – 3 September 1829) was a soldier, born in Ulster, Ireland. He ran away from home when a boy, enlisted in the British army, and served under General John Burgoyne during the American Revolutionary War. After the surrender at Saratoga, John returned to England and was honorably discharged. Soon afterward, he eloped with Anna, a daughter of Sir Edward Bishop, a friend of his father. They emigrated to the United States, and settled at Hagerstown, Maryland.
Shortly afterward, John entered the United States Army, and was sent to the Western frontier. He was sent on the Harmar Campaign of 1790, and was severely wounded in St. Clair's Defeat of 1791. He was a lieutenant in the Legion of the United States, and helped build the United States forts in Fort Wayne. He was promoted to captain on 1 July 1797 and transferred to Fort Lernoult in Detroit. In Summer 1803, he was sent with his company of the 1st Infantry from Fort Detroit to Lake Michigan, where he completed Fort Dearborn before the close of the year, on the site of the future city of Chicago. He served as the first commandant of the new fort.
Captain Whistler was recalled to Detroit in 1810. During the War of 1812, he was breveted to major, and served with his company until the end of the war in 1815. After the war, he was appointed military store-keeper at Newport, Kentucky. In 1816, he was sent to Fort Wayne where he built the third fort there; having helped design the first two. In 1817 he moved to St. Charles, Missouri, and was the military storekeeper at Jefferson Barracks, near St. Louis, Missouri, a position he held until his death at Fort Bellefontaine in 1829.