British forces abandon the Siege of Fort Stanwix after hearing rumors of Continental Army reinforcements.

The siege of Fort Stanwix began on August 2, 1777, and ended on August 22, 1777. Fort Stanwix, at the western end of the Mohawk River Valley, was a primary defense point for the Continental Army against the British and indigenous forces aligned against them during the American Revolutionary War. The fort was occupied by Continental Army forces from New York and Massachusetts under the command of Colonel Peter Gansevoort. The besieging force was composed of British regulars, Loyalist soldiers, Hessians, and indigenous warriors, under the command of Brigadier General Barry St. Leger. St. Leger's expedition was a diversion in support of Lieutenant General John Burgoyne's campaign to take control of the Hudson River Valley to the east.

The Continental Army was the army of the United Colonies representing the Thirteen Colonies and later the United States during the American Revolutionary War. It was formed on June 14, 1775, by a resolution passed by the Second Continental Congress, meeting in Philadelphia after the war's outbreak at the Battles of Lexington and Concord on April 19, 1775. As a result, the U.S. Army Birthday is celebrated on June 14.