Herkimer County is a county in the U.S. state of New York. As of the 2020 census, the population was 60,139. Its county seat is Herkimer. The county was created in 1791 north of the Mohawk River out of part of Montgomery County. It is named after General Nicholas Herkimer, who died from battle wounds in 1777 after taking part in the Battle of Oriskany during the Revolutionary War.

The Battle of Oriskany was a significant engagement of the Saratoga campaign of the American Revolutionary War, and one of the bloodiest battles in the conflict between Patriot forces and those loyal to Great Britain. On August 6, 1777, several hundred of Britain's Indigenous allies, accompanied by Loyalists of the King's Royal Regiment of New York and the British Indian Department, ambushed a Patriot militia column which was marching to relieve the siege of Fort Stanwix. This was one of the few battles in which the majority of the participants were American colonists. Patriots and allied Oneidas fought against Loyalists and allied Iroquois and Mississaugas. No British regulars were involved; however, a detachment of Hessians was present.