American Revolution: Siege of Fort Stanwix

Peter Gansevoort
Colonel Peter Gansevoort. Public Domain

The Siege of Fort Stanwix was conducted from August 2 to 22, 1777, during the American Revolution (1775-1783) and was part of the Saratoga Campaign. In an effort to split New England from the rest of the colonies, Major General John Burgoyne advanced south over Lake Champlain in 1777. To support his operations, he dispatched a force to advance east from Lake Ontario led by Brigadier General Barry St. Leger. Aided by Native American warriors, St. Leger's column laid siege to Fort Stanwix in August. Though an initial American attempt to relieve the garrison was defeated at Oriskany on August 6, a subsequent effort led by Major General Benedict Arnold succeeded in forcing St. Leger to retreat.


In early 1777, Major General John Burgoyne proposed a plan for defeating the American rebellion. Convinced that New England was the seat of the revolt, he proposed severing the region from the other colonies by advancing down the Lake Champlain-Hudson River corridor while a second force, led by Lieutenant Colonel Barry St. Leger, moved east from Lake Ontario and through the Mohawk Valley. Meeting at Albany, Burgoyne and St. Leger would advance down the Hudson, while General Sir William Howe's army advanced north from New York City. Though approved by Colonial Secretary Lord George Germain, Howe's role in the plan was never clearly defined and issues of his seniority precluded Burgoyne from issuing him orders.

John Burgoyne in a red British Army uniform.
General John Burgoyne. Public Domain

St. Leger Prepares

Gathering near Montreal, St. Leger's command was centered on the 8th and 34th Regiments of Foot, but also included forces of Loyalists and Hessians. To aid St. Leger in dealing with militia officers and the Native Americans, Burgoyne gave him a brevet promotion to brigadier general prior to embarking. Assessing his line of advance, St. Leger's largest obstacle was Fort Stanwix located at the Oneida Carrying Place between Lake Oneida and the Mohawk River. Built during the French & Indian War, it had fallen into disrepair and was believed to have a garrison of around sixty men. To deal with the fort, St. Leger brought along four light guns and four small mortars (Map).

Strengthening the Fort

In April 1777, General Philip Schuyler, commanding American forces on the northern frontier, became increasingly concerned about the threat of British and Native American attacks via the Mohawk River corridor. As a deterrent, he dispatched Colonel Peter Gansevoort's 3rd New York Regiment to Fort Stanwix. Arriving in May, Gansevoort's men began working to repair and enhance the fort's defenses.

Though they officially renamed the installation Fort Schuyler, its original name continued to be widely used. In early July, Gansevoort received word from friendly Oneidas that St. Leger was on the move. Concerned about his supply situation, he contacted Schuyler and requested additional ammunition and provisions.

Siege of Fort Stanwix

  • Conflict: American Revolution (1775-1783)
  • Dates: August 2-22, 1777
  • Armies and Commanders
  • Americans
  • Colonel Peter Gansevoort
  • 750 men at Fort Stanwix
  • Major General Benedict Arnold
  • 700-1,000 men in relief force
  • British
  • Brigadier General Barry St. Leger
  • 1,550 men

The British Arrive

Advancing up the St. Lawrence River and onto Lake Ontario, St. Leger received word that Fort Stanwix had been reinforced and was garrisoned by around 600 men. Reaching Oswego on July 14, he worked with Indian Agent Daniel Claus and recruited around 800 Native American warriors led by Joseph Brant. These additions swelled his command to around 1,550 men.

Joseph Brant in Native American dress with headdress
Mohawk leader Joseph Brant.  Public Domain

Moving west, St. Leger soon learned that the supplies Gansevoort had requested were nearing the fort. In an effort to intercept this convoy, he sent Brant ahead with around 230 men. Reaching Fort Stanwix on August 2, Brant's men appeared just after elements of the 9th Massachusetts had arrived with the supplies. Remaining at Fort Stanwix, the Massachusetts troops swelled the garrison to around 750-800 men.

The Siege Begins

Assuming a position outside the fort, Brant was joined by St. Leger and the main body the next day. Though his artillery was still en route, the British commander demanded Fort Stanwix's surrender that afternoon. After this was refused by Gansevoort, St. Leger began siege operations with his regulars making camp to the north and the Native Americans and Loyalists to the south.

During the first few days of the siege, the British struggled to bring their artillery up nearby Wood Creek which was blocked by trees felled by the Tryon County militia. On August 5, St. Leger was informed that an American relief column was moving towards the fort. This was largely composed of the Tryon County militia led by Brigadier General Nicholas Herkimer.

Battle of Oriskany

Responding to this new threat, St. Leger dispatched around 800 men, led by Sir John Johnson, to intercept Herkimer. This included the bulk of his European troops as well as some Native Americans. Setting an ambush near Oriskany Creek, he attacked the approaching Americans the next day. In the resulting Battle of Oriskany, both sides inflicted substantial losses on the other.

Though the Americans were left holding the battlefield, they were unable to push on to Fort Stanwix. Despite achieving a victory, British and Native American morale was damaged by the fact that Gansevoort's executive officer, Lieutenant Colonel Marinus Willett, had led a sortie from the fort which attacked the their camps. In the course of the raid, Willett's men carried off many of the Native American's possessions as well as captured many British documents including St. Leger's plans for the campaign.

Brigadier General Nicholas Herkimer directing troops during the Battle of Oriskany.
Brigadier General Nicholas Herkimer at the Battle of Oriskany. Public Domain

Returning from Oriskany, many of the Native Americans were irate over the loss of their belongings and the casualties sustained in the fighting. Learning of Johnson's triumph, St. Leger again demanded the fort's surrender but to no avail. On August 8, the British artillery finally deployed and began firing on Fort Stanwix's northern wall and northeastern bastion.

Though this fire had little effect, St. Leger again requested that Gansevoort capitulate, this time threatening to turn loose the Native Americans to attack settlements in the Mohawk Valley. Responding, Willett stated, "By your uniform you are British officers. Therefore let me tell you that the message you have brought is a degrading one for a British officer to send and by no means reputable for a British officer to carry."

Relief at Last

That evening, Gansevoort ordered Willett take a small party through the enemy lines to seek help. Moving through the marshes, Willett was able to escape east. Learning of the defeat at Oriskany, Schuyler resolved to send a new relief force from his army. Led by Major General Benedict Arnold, this column was composed of 700 regulars from the Continental Army.

Moving west, Arnold encountered Willett before pressing on to Fort Dayton near German Flatts. Arriving on August 20, he wished to wait for additional reinforcements before proceeding. This plan was dashed when Arnold learned that St. Leger had begun entrenching in an effort to move his guns closer to Fort Stanwix's powder magazine. Unsure about proceeding without additional manpower, Arnold elected to use deception in an effort to disrupt the siege.

Engraving of Benedict Arnold in his Continental Army uniform.
Major General Benedict Arnold. National Archives & Records Administration

Turning to Han Yost Schuyler, a captured Loyalist spy, Arnold offered the man his life in exchange for returning to St. Leger's camp and spreading rumors about an impending attack by a large American force. To ensure Schuyler's compliance, his brother was held as a hostage. Traveling to the siege lines at Fort Stanwix, Schuyler spread this tale among the already unhappy Native Americans.

Word of Arnold's "assault" soon reached St. Leger who came to believe the American commander was advancing with 3,000 men. Holding a council of war on August 21, St. Leger found that part of his Native American contingent had already departed and that remainder was preparing to leave if he did not end the siege. Seeing little choice, the British leader broke off the siege the next day and began withdrawing back towards Lake Oneida.


Pressing forward, Arnold's column reached Fort Stanwix late on August 23. The next day, he ordered 500 men to pursue the retreating enemy. These reached the lake just as the last of St. Leger's boats were departing. After securing the area, Arnold withdrew to rejoin Schuyler's main army. Retreating back to Lake Ontario, St. Leger and his men were taunted by their erstwhile Native American allies. Seeking to rejoin Burgoyne, St. Leger and his men traveled back up the St. Lawrence and down Lake Champlain before arriving at Fort Ticonderoga in late September.

While the casualties during the actual Siege of Fort Stanwix were light, the strategic consequences proved substantial. The defeat of St. Leger prevented his force from uniting with Burgoyne and disrupted the larger British plan. Continuing to push down the Hudson Valley, Burgoyne was halted and decisively defeated by American troops at the Battle of Saratoga. The turning point of the war, the triumph led to the critical Treaty of Alliance with France.

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Hickman, Kennedy. "American Revolution: Siege of Fort Stanwix." ThoughtCo, Apr. 5, 2023, Hickman, Kennedy. (2023, April 5). American Revolution: Siege of Fort Stanwix. Retrieved from Hickman, Kennedy. "American Revolution: Siege of Fort Stanwix." ThoughtCo. (accessed May 30, 2023).