On this day in 1779, at what is modern-day Elmira, New York, near the state's southwestern border with Pennsylvania, Continental forces led by Major General John Sullivan and Brigadier General James Clinton defeat a combined force of Loyalists and Indians commanded by Captain Walter Butler and Chief Joseph Brant.
The Continental commander in chief, General George Washington, gave Sullivan orders to attack the Iroquois of the Finger Lakes region, who were allied with the British, in what is known as the "Sullivan Expedition." Washington had first requested General Horatio Gates to challenge the Iroquois, but Gates refused. Washington then turned to Sullivan, who accepted the challenge. Sullivan traveled up the Susquehanna River from Easton, Pennsylvania, to the Chemung (or "big horn") Basin, named for a mammoth tusk found in the Chemung River by Native Americans. The river provided both a means of transport and sustenance for the Iroquois of the surrounding region.
The Continentals discovered a breastwork of 80 rods erected by the combined Iroquois-Loyalist force that hoped to ambush the Patriots as they marched north towards Lake Erie and the British forts at Oswego and Niagara. The Patriots then managed to use their artillery to drive off the Indians. Sullivan subsequently embarked on a scorched-earth campaign against the Iroquois in retaliation for their continued raids against frontier settlements. At least 40 of the tribe's villages were destroyed, along with valuable supplies. As a result, the winter of 1779 was particularly brutal for the Iroquois. Nonetheless, they managed to increase their pressure on frontier settlements in 1780.
Despite the best efforts of the Iroquois, the Chemung Valley fell into the hands of American settlers following the war. As a result, Iroquois attached to Chief Joseph Brandt followed him in a resettlement to Canada.
The Battle of Chemung is re-enacted annually at Newtown Battlefield State Park in Elmira, New York.