Johan Jost Herkimer (Herchmer or Hercheimer c. 1732 – August 1795 ) was a Loyalist born in 1732, the second of five sons of Johan Jost Herkimer and Anna Catherine Herkimer of German Flatts, New York. He was the younger brother of the American Patriot General Nicholas Herkimer.
Like his brother Nicholas, Johan was an established landowner and an officer in the Tryon County militia. Unlike his brother, he decided to stand for the British King when the American War of Independence broke out. This decision alienated him from his elder brother Nicholas who sided with the new Continental Congress and he was sorely tested by social ostracism. Because of his actions, Johan spent time in patriot jails between 1775 and 1777, and was subjected to house arrest. In March 1777 he managed to escape and made his way to Fort Niagara. His popularity with the Indians and his knowledge of native customs resulted in his being attached to the Indian Department with the rank of Captain.
In the summer of 1777 he returned to New York as part of St. Leger's expedition under the command of General Barry St. Leger. He participated in the expedition as overseer of boats, and he and Captain Rouville of the Canadians successfully broke up the Patriots’ blockade of Wood Creek. He was also present at the siege of Fort Stanwix and the battle of Oriskany on 6 August 1777 where the British and their Mohawk allies ambushed American forces on their way to relieve Fort Stanwix. His Brother, Nicholas, was severely wounded at this battle as he commanded the American Militia and died ten days later.