The abandoned Fort Stanwix was reconstructed by American forces and named Fort Schuyler. In 1777 the fort was attacked by British forces under the General St. Leger as part of a three-pronged attack to split American power in New York State. The fort commander, Colonel Peter Gansevoort, refused the terms of surrender offered by the British, and the seige commenced.

The Battle of Oriskany was fought when an American relief column, commanded by General Nicholas Herkimer was ambushed by British troops, Tories, and their indian allies. While many of the besiegers were attending to that battle, the defenders of the fort sallyed forth and attacked the enemy camp, looting and destroying enemy stores. Demoralized and reduced in strength, the British withdrew when they heard rumors of yet another relief column, led by General Benedict Arnold. The Britsh failure to capture the fort and procede down the Mohawk Valley was a severe setback and eventually led to the defeat of General John Burgoyne at the Battle of Saratoga.