The Battle of Oriskany was a major engagement of the Saratoga campaign during the American Revolutionary War. On August 6, 1777, an American column of Tryon County militia and Oneidas marching to relieve the siege of Fort Stanwix was ambushed by a contingent of Britain's Indigenous allies and Loyalists. It was one of the few battles of the war in which most non-Indigenous participants were settlers born in the Thirteen Colonies. The Americans suffered heavy casualties during the battle. Alerted to the possibility of a British attack along the Mohawk River, Nicholas Herkimer, the head of Tryon County's Committee of Safety, issued a proclamation on July 17 warning of possible military activity and urging the people to respond if needed. Warned by friendly Oneidas on July 30 that the British were just four days from Fort Stanwix, Herkimer put out a call-to-arms. The force raised totaled 800 from the Tryon County militia; it was composed primarily of poorly trained farmers, who were chiefly of Palatine German descent. On August 4, the column marched out and then camped near the Oneida village of Oriska on August 5. While a number of the militia dropped out of the column due to their lack of conditioning, Herkimer's forces were augmented by a company of 60 to 100 Oneida warriors, led primarily by Han Yerry.

Herkimer held a war council on the morning of August 6. He wanted to wait because he had not heard the expected signal from the fort, but his captains pressed him to continue, accusing him of being a Tory because his brother was serving under St. Leger. He was stung by the accusations and relented, ordering the column to march on toward Stanwix. The trap had been sprung too early, and portions of the column had not yet entered the ravine. Most of these men panicked and fled; some of the attacking warriors pursued them, resulting in a string of dead and wounded that extended for several miles. Between the loss of the column rear and those killed or wounded in the initial volleys, only about one half of Herkimer's men were still fighting 30 minutes into the battle. Herkimer's messengers reached the fort at around 11 a.m., and Colonel Gansevoort organized the requested sortie. Lieutenant Colonel Marinus Willett led 250 men from the fort and raided the nearly deserted enemy camps to the south, driving away the few people left in them (including women) and taking four prisoners along the way. They collected blankets and other personal possessions from the indigenous camps, and they also raided John Johnson's camp, taking his letters and other writings. Upon the withdrawal of the Natives and Loyalists, the Patriots who had not fled the scene attended to the evacuation of wounded, some of whom were taken by boat downriver to safety. Many wounded Patriots were left on the field. The dead were not buried for several years.