The siege of Fort Stanwix (also known as Fort Schuyler) began on August 2, 1777 and ended on August 22, 1777. Fort Stanwix, at the western end of the Mohawk River Valley, was a primary defense point for the Continental Army against the British and indigenous forces aligned against them during the American Revolutionary War. The fort was occupied by Continental Army forces from New York and Massachusetts under the command of Colonel Peter Gansevoort. The besieging force was composed of British regulars, Loyalist soldiers, Hessians, and indigenous warriors, under the command of Brigadier General Barry St. Leger. St. Leger's expedition was a diversion in support of Lieutenant General John Burgoyne's campaign to take control of the Hudson River Valley to the east.
One attempt at relief was thwarted early in the siege when a force of New York militia under Brigadier General Nicholas Herkimer was ambushed on August 6 at the Battle of Oriskany by a large detachment of St. Leger's forces. While the battle did not involve the fort's garrison, some of its occupants sortied and plundered the nearly empty indigenous and Loyalist camps, which was a blow to the morale of St. Leger's indigenous allies. The siege was finally broken when American reinforcements under the command of Major General Benedict Arnold approached, and Arnold used a ruse to convince the besiegers that he had a much larger force. This misinformation, combined with the departure of many of the indigenous warriors, led St. Leger to abandon the effort and withdraw.
St. Leger's failure to advance on Albany contributed to Burgoyne's surrender following the Battles of Saratoga in October 1777. Although St. Leger reached Fort Ticonderoga with some of his forces in late September, he was too late to aid Burgoyne.
Background
Fort Stanwix occupied a strategic western portage known as the Oneida Carrying Place (site of modern Rome, New York) between the Mohawk River, which flowed southeast to the Hudson River, and Wood Creek, whose waters ultimately led to Lake Ontario. Built by the British in 1758 during the French and Indian War on the only dry ground in the area, the fort had fallen into disrepair. When the American Revolutionary War widened in 1776 to include the frontier areas between New York and the Province of Quebec, the site again became strategically important.
British Colonial Secretary Lord Germain and General John Burgoyne developed a plan for gaining control of the Hudson River valley that included an expedition that King George described as a "diversion on the Mohawk River". In March 1777 Germain issued orders assigning the expedition to Lieutenant Colonel Barry St. Leger, an experienced frontier fighter who had served in the French and Indian War.
Forces assemble
In April 1777, Continental Army Major General Philip Schuyler ordered the 3rd New York Regiment under the command of Colonel Peter Gansevoort to occupy and rehabilitate Fort Stanwix as a defense against British and indigenous incursions from Quebec. Arriving in May, they immediately began working on the fort's defenses. Although officially renamed Fort Schuyler, it was still widely known by its original name. Warnings from the Oneida that the British were planning an expedition were confirmed by mid-July, spurring the pace of the work. In early July, Gansevoort reported on the state of affairs to Schuyler, noting that provisions and ammunition were in short supply. Schuyler ordered additional supplies sent to the fort on July 8. Later that month the 3rd New York were joined by a 150 man detachment of the 9th Massachusetts Regiment.
St. Leger, who was brevetted a brigadier general for the expedition, assembled a diverse force consisting of about 240 British regulars from the 8th Regiment of Foot, 34th Regiment of Foot and the Royal Artillery, 250 Loyalists from the King's Royal Regiment of New York (also known as the Royal Yorkers), 90 jäger from Hesse-Hanau, and 50 Canadien laborers. His artillery consisted of two six-pound pieces, two three-pounders and four coehorn mortars. He expected these to be adequate for the taking of a dilapidated fort with about 60 defenders, which was the latest intelligence he had when the expedition left Lachine, near Montreal, on June 26.