While the campaign had only one major battle at Newtown on the Chemung River in western New York, the expedition severely damaged the Iroquois nations' economies by destroying their crops, villages, and chattels.

Working out of Fort Niagara, men such as Loyalist commander Major John Butler, Mohawk military leader Joseph Brant, and Seneca war chiefs Sayenqueraghta and Cornplanter led the joint British-Indigenous raids.

Since a defensive war would prove inadequate, the board called for an expedition of 3,000 men against Fort Detroit and a similar thrust into Seneca country to punish the Iroquois.

[6][7] In September 1778, a response to the Wyoming defeat was undertaken by Colonel Thomas Hartley who destroyed a number of abandoned Delaware and Seneca villages along the Susquehanna River, including Tioga.

[4] In October, further American retaliation was taken by Continental Army units under Lieutenant Colonel William Butler who destroyed the substantial Indigenous villages at Unadilla and Onaquaga on the Susquehanna River.

While the rangers and regulars blockaded Fort Alden, the Seneca rampaged through the village, killing and scalping 16 soldiers and 32 civilians, mostly women and children, and taking 80 captives.

It is likely enough their fears if they are unable to oppose us, will compel them to offers of peace, or policy may lead them, to endeavour to amuse us in this way to gain time and succour for more effectual opposition.

[6] Supply shortages delayed Sullivan's departure from Wyoming until July 31 when the expedition set out for Tioga at the confluence of the Chemung and Susquehanna rivers.

[6][12] After arriving at Tioga, Sullivan dispatched a small party to reconnoitre Chemung, a Delaware village 12 miles (19 km) upstream, where he believed Indigenous and Loyalist forces were gathering.

[4] After destroying Chenussio's 128 houses with its gardens and cornfields, Sullivan retraced his steps, aware that provisions were growing short, and mistakenly believing there were no other Seneca villages west of the Genesee River.

Washington's strategy for the "chastisement of the savages" initially included an operation from Fort Pitt, but in April 1779, he had ordered the expedition cancelled due to supply issues.

Gansevoort's actions were criticized by Philip Schuyler, Commissioner for Indian Affairs and member of the Continental Congress, because the captured Mohawks were strictly neutral.

As a result he focused on reinforcing the defences of the St. Lawrence River valley rather than supporting Britain's Iroquois allies by establishing a long-promised post at Oswego on Lake Ontario or increasing troop strength at Fort Niagara.

If anything is really intended against the Upper Country, I am convinced that Detroit is the object and that they show themselves and spread reports of an expedition in your neighbourhood merely to divert the Rangers and Indians from their main purpose.

[24] In response, Haldimand wrote directly to Butler in August reaffirming his belief that Fort Detroit was the target and that the American forces on the Susquehanna were a feint.

He ordered Sir John Johnson to take command of a 400-man relief expedition that would proceed from Lachine up the St Lawrence River to Carleton Island.

Sullivan elaborated further in a letter to Congress dated November 9, 1779: "My Heal⟨th⟩ is so much impair’d by a violent bilious disorder, which seize⟨d⟩ me in the commencement, and continued during the whole of the western expedition."

[4] Francis Goring, an employee of the trading firm Taylor & Forsyth, described the conditions at Fort Niagara in an October 1780 letter to his uncle: I cannot help mentioning that last winter was the severest that was ever felt here.

Guy Johnson, the Superintendent of the British Indian Department, ordered the messengers imprisoned in Fort Niagara's "black hole," an unheated, unlit stone cell.

Although the destruction of their villages and crops forced the Iroquois to take refuge at Fort Niagara and put considerable strain on British resources, it also triggered devastating revenge attacks.

In May 1780, Iroquois warriors accompanied Sir John Johnson and the King's Royal Regiment of New York in a raid that destroyed every building in Caughnawaga except for the church.

In total, the Mohawk and Schoharie valleys saw 330 men, women and children killed or taken prisoner, six forts and several mills destroyed, and over 700 houses and barns burned in 1780.

The Six Nations in council at Buffalo Creek, however, refused to ratify the treaty, denying that their delegates had the authority to surrender such large tracts of land.

Jeffrey Ostler estimates that the number killed by direct military action was around 200 (including some women and children), with as many as 1,000 later dying in refugee camps from starvation or disease.

[46] Alan Taylor in The Divided Ground also reports "several hundred" deaths[3] as does Rachel Herrmann of Cardiff University who uniquely describes the Sullivan campaign as "victual warfare.

Koehler further states that between 473 and 580 men, women and children died from direct military action, however, neither of the sources she cites appear to support her assertion.

In his speech, Sherman justified Sullivan's "scorched earth" campaign and the displacement of Indigenous people by appealing to the widespread American 19th-century belief in manifest destiny.

[50] He told his audience, "Wherever men raise up their hands to oppose this great advancing tide of civilization, they must be swept aside, peaceably if possible, forcibly if we must.

The brass plaque mounted on each of the monoliths bears an inscription that perpetuates the false narrative that Sullivan "did conquer the Indians and forever stopped their depredations.

[52] That same year, the United States Post Office issued a commemorative two-cent red stamp featuring a portrait of Major General Sullivan.