The 1779 Sullivan Expedition was a United States military campaign during the American Revolutionary War, lasting from June to October 1779, against the four British allied nations of the Iroquois (also known as the Haudenosaunee). The campaign was ordered by George Washington in response to the 1778 Iroquois and British attacks on Wyoming, German Flatts, and Cherry Valley. The campaign had the aim of "taking the war home to the enemy to break their morale".^[52] The Continental Army carried out a scorched-earth campaign in the territory of the Iroquois Confederacy in what is now western and central New York.

The expedition was largely successful, with more than 40 Iroquois villages razed and their crops and food stores destroyed. The campaign drove 5,000 Iroquois to Fort Niagara seeking British protection. The campaign depopulated the area for post-war settlement and opened up the vast Ohio Country, Western Pennsylvania, West Virginia, and Kentucky to post-war settlement. Some scholars argue that it was an attempt to annihilate the Iroquois and describe the expedition as a genocide,^[53] although this term is disputed, and it is not commonly used when discussing the expedition. Historian Fred Anderson, describes the expedition as "close to ethnic cleansing" instead.^[54] Some historians have also related this campaign to the concept of total war, in the sense that the total destruction of the enemy was on the table.^[55]