Key figures: Lieutenant Colonel Barry St. Leger (British expedition commander), Colonel Peter Gansevoort (American, Fort Stanwix garrison commander), Lieutenant Colonel Marinus Willett (American, Fort Stanwix), Brigadier General Nicholas Herkimer (American, Tryon County militia, mortally wounded), Sir John Johnson (British/Loyalist), Joseph Brant (Mohawk war leader, British-allied), Major General Benedict Arnold (American, relief expedition), Samuel Kirkland (Presbyterian missionary to the Oneida)
Summary
In January 1777, the sudden death of some ninety Onondaga chiefs — most likely from smallpox — extinguished the Six Nations’ central council fire at Onondaga, ending the Iroquois Confederacy’s centuries-old practice of unified diplomatic action and freeing its member nations to choose sides individually in the Revolutionary War. Four nations — the Mohawk, Onondaga, Cayuga, and Seneca — aligned with Britain, while the Oneida and Tuscarora, influenced by missionary Samuel Kirkland, supported the American cause. That split erupted into open warfare on August 6, 1777, at the Battle of Oriskany, fought as Tryon County militia under Nicholas Herkimer attempted to relieve Lieutenant Colonel Barry St. Leger’s siege of Fort Stanwix — the western prong of General John Burgoyne’s three-pronged campaign to sever New England from the other colonies. The ambush was catastrophic for the relief column but, combined with a subordinate raid and a subsequent deception of St. Leger’s Native allies, ultimately forced St. Leger to abandon the siege on August 22, denying Burgoyne the reinforcement he needed before his surrender at Saratoga two months later.
The Onondaga Council Fire and the Confederacy Split
The Six Nations of the Iroquois Confederacy — Mohawk, Oneida, Onondaga, Cayuga, Seneca, and Tuscarora — had for generations acted as a unified diplomatic bloc, with the Onondaga serving as “Keepers of the Central Fire” at the confederacy’s symbolic capital. In January 1777, an Onondaga sachem reported that roughly ninety of the nation’s most powerful chiefs had died in rapid succession, likely victims of a smallpox outbreak — the same disease that in early 1777 prompted General George Washington to mandate mass inoculation of all incoming Continental troops, the largest coordinated preventive medicine program in North American history to that date. With no established leaders to convene it, the central council fire was declared extinguished, and with it the mechanism by which the Six Nations reached collective policy. Individual nations, and in some cases individual communities and families within nations, became free to choose their own course in the Anglo-American conflict.
The Mohawk, Onondaga, Cayuga, and Seneca — the majority — sided with the Crown, driven in large part by decades of alliance with the British Indian Department under the late Sir William Johnson and his successors, including his nephew Guy Johnson and son Sir John Johnson. The Oneida and Tuscarora broke with this majority and supported the American cause, a shift substantially shaped by Samuel Kirkland, a Presbyterian missionary who had lived among the Oneida since the 1760s, cultivated deep personal ties, and served as an intelligence source for the Continental Congress and General Washington. The division marked the first time in the confederacy’s history that its constituent nations took up arms against one another.
St. Leger’s Expedition and the Siege of Fort Stanwix
Fort Stanwix (renamed Fort Schuyler by the Americans), at present-day Rome, New York, guarded the Oneida Carrying Place linking the Mohawk River to Lake Ontario — the western approach to the Mohawk Valley and, ultimately, Albany. As the western column of Burgoyne’s 1777 campaign — approved in London by Secretary of State Lord George Germain, who simultaneously sanctioned General Howe’s Philadelphia expedition without making the two operations explicitly contingent on each other — Lieutenant Colonel Barry St. Leger led roughly 240 British regulars, 250 Loyalists, 90 Hessians, and about 800 allied Native warriors — mostly Seneca and Cayuga, led in part by the Mohawk war leader Joseph Brant — from Lake Ontario toward the fort, arriving to begin the siege on August 2, 1777. Colonel Peter Gansevoort commanded the American garrison of roughly 750 Continentals of the 3rd New York Regiment, reinforced during the siege by about 150 Massachusetts troops who slipped through the besieging lines.
The Battle of Oriskany
On learning of the siege, Brigadier General Nicholas Herkimer assembled some 800 Tryon County militiamen, joined by 60 to 100 Oneida warriors, and marched to relieve the fort. On August 6, 1777, St. Leger dispatched Sir John Johnson with a mixed force of about 100 Loyalists and roughly 400 Mohawk and other Native warriors to intercept the column at a wooded ravine near the village of Oriskany, six miles from the fort.
The ambush opened at approximately 10 AM when the advance and rear of Herkimer’s column had passed into the ravine but the main body was still exposed on the slope — a classic envelopment that initially trapped the Americans in a deadly crossfire. Herkimer himself was struck in the leg within minutes of the first shots; rather than leave the field, he had his saddle brought to a beech tree, sat propped against it, and continued directing the fight while calmly smoking his pipe. After the initial shock, the Americans regrouped into a tighter defensive perimeter, back-to-back in pairs to prevent warriors from tomahawking from behind. About an hour into the fighting, a summer thunderstorm forced a lull of roughly an hour; when it lifted, the two sides continued in brutal close-quarters combat — musket, bayonet, and hatchet — until Johnson’s force finally broke off around 4 PM.
The engagement inflicted devastating losses: American casualties totaled roughly 385 killed, with dozens more wounded or captured, out of a force of some 800 to 900 — among the proportionally bloodiest engagements of the entire Revolutionary War. Herkimer died of complications from the amputation of his leg on August 16. British and Loyalist losses were comparatively light — about 7 killed and 21 wounded — but their Native allies suffered heavily, with dozens of warriors and a disproportionate number of war chiefs killed. Despite the mauling, Herkimer’s survivors held the field and forced Johnson’s detachment to break off, while Lieutenant Colonel Marinus Willett led a sortie of 250 men from the fort that plundered the undefended British and Native camps during the battle — a raid whose loss of provisions and personal property embittered St. Leger’s Native allies against the campaign.
The Willett Sortie and Its Material Consequences
The 250-man sortie that Lieutenant Colonel Marinus Willett launched from Fort Stanwix during the battle achieved results that went well beyond the immediate raid. Moving through the lightly guarded perimeter while St. Leger’s forces were committed at Oriskany, Willett’s column swept through at least three British and Loyalist camps, seizing five packhorses loaded with provisions and camp equipment, roughly twenty-one wagonloads of supplies and blankets, and — most consequentially — the personal correspondence and papers of Sir John Johnson, commander of the Loyalist force. Those documents revealed by name the Mohawk Valley Loyalists who had been informing for the Crown, enabling American authorities to identify and neutralize Loyalist intelligence networks in the valley for years afterward.
The raid’s psychological effect on St. Leger’s Native allies was disproportionate to its scale. For Seneca and Mohawk warriors, the loss of personal property, camp equipment, and war matériel from an unguarded perimeter — while their chiefs and warriors were dying in the ravine at Oriskany — signaled that British protection had failed within its own lines. The loss of perhaps dozens of war chiefs at Oriskany, combined with the plunder of their camps, shattered the morale and unit cohesion of the allied warriors and made them susceptible to exactly the kind of rumor Arnold would later deploy.
Willett followed the sortie with a personal act of equal audacity: accompanied by Lieutenant Stockwell, he slipped out of the besieged fort at night, evaded the British lines, and traveled on foot through swamp and forest to Fort Dayton, roughly thirty miles to the east, carrying word of the garrison’s situation. From there the two men pressed on to General Philip Schuyler’s headquarters, where their firsthand account of the garrison’s strength and the siege’s progress helped persuade Schuyler to convene a council of war and dispatch a relief expedition under Arnold — closing the chain of subordinate actions that ultimately undid St. Leger’s campaign without the need for a second major engagement.
Siege’s End and the Confederacy at War
News of the losses at Oriskany, compounded by the camp raid, eroded the morale of St. Leger’s Native allies. In mid-August, Major General Benedict Arnold marched a relief force of roughly 700 Continentals from Fort Dayton toward Stanwix and reinforced this pressure with a ruse: a captured Loyalist, Hon Yost Schuyler, was induced — his brother held hostage — to warn St. Leger’s camp that Arnold was approaching with an overwhelming force, reportedly numbering in the thousands. Several Oneida warriors accompanying the ruse amplified the story, each arriving separately at St. Leger’s camp to repeat and embroider the tale, a tactic the Oneida later described as using wampum to carry false tidings of war. The number Schuyler reportedly communicated — as many as 8,000 approaching troops, roughly eight times Arnold’s actual force of under 900 men — was made all the more alarming by Schuyler’s dramatic gestures: contemporaries recorded that he pointed to the leaves on the trees to indicate the number, a comparison that conjured near-infinite reinforcements. Schuyler had also been instructed to make coded marks on his coat to signal to Arnold’s advancing column how the deception was faring inside the camp — making the episode one of the earliest documented American military deception operations, remarkable both for its audacity and for its successful fusion of Continental Army initiative and Oneida cultural knowledge. Combined with dwindling supplies and the desertion of many of his Native allies, the deception led St. Leger to abandon the siege and retreat toward Oswego on August 22, 1777, ending the western prong of Burgoyne’s campaign without ever reaching the Mohawk Valley in force.
The Battle of Oriskany also opened a period of internecine violence within the former confederacy. In its aftermath, British-allied sachems formally declared war on the Oneida, and Loyalist and allied Native raiding parties struck Oneida and Tuscarora villages throughout the remainder of the war, while American and Oneida forces struck back at Mohawk and Seneca and Cayuga settlements, culminating in the destructive Sullivan Expedition against the four British-aligned nations in 1779. The destruction of Oneida villages by British-allied forces, and the parallel dispossession of British-aligned Cherokee by American forces formalized in the Treaty of Long Island of the Holston that same July, reflected a continent-wide pattern in 1777 in which Britain’s Native alliances collapsed under the weight of the war’s costs while Britain’s strategic ambitions — severing New England in the north and securing the southern backcountry — remained unfulfilled.
The Oneida and the Aftermath
The Oneida paid a steep price for their alliance with the Americans. By war’s end, Oneida and Tuscarora villages had been burned multiple times by British-allied forces, and the nation’s surviving population was largely displaced. The Oneida formally received recognition of their wartime service in the Treaty of Paris negotiations, but the post-war land settlement left them confined to a sharply reduced territory in central New York, and subsequent legal and political pressure through the 1780s and 1790s stripped them of most of what remained. Their sacrifice at Oriskany — the first time members of the Six Nations fought against one another in open battle — was recognized two centuries later when the U.S. Congress awarded a Congressional Gold Medal to the Oneida Nation in 1998 for their Revolutionary War service.
Significance
The failure of St. Leger’s expedition denied Burgoyne the western reinforcement his plan required and contributed directly to his isolation and eventual surrender at Saratoga on October 17, 1777 — the turning point that persuaded France to enter the war as an American ally. The same August saw American forces win at Bennington and strip Burgoyne of his cavalry and supply; Oriskany and Bennington together sealed Burgoyne’s strategic isolation before the first clash at Saratoga on September 19. Beyond its military effect, the events of January through August 1777 permanently fractured the Iroquois Confederacy. The war that erupted between its member nations at Oriskany displaced thousands of Native people, destroyed longstanding structures of collective Haudenosaunee governance, and set in motion a cycle of raid and retaliation that, compounded by the 1779 Sullivan Expedition, devastated Iroquoia and reshaped Native political life in New York for generations after the Revolution ended.