In the summer of 1777, while the British and the Americans were engaged in the bitter American Revolution, a massive campaign was launched from Canada into New York State.

Brigadier Barry St. Leger led a crucial expedition from Lake Ontario into the Mohawk Valley. The goal was to travel by waterways to join Lieutenant General John Burgoyne in the siege of Albany. But Leger encountered obstacles along the way. While laying siege to Fort Stanwix, Leger received word that Benedict Arnold was leading a massive relief column that was headed their way. Leger and his men retreated, and despite a later attempt to carry on, were never able to help Burgoyne. The Americans then destroyed the British-held Fort Ticonderoga, marking the end of the campaign.

The results of the failed St. Leger expedition were historic. Not only was the loss of Fort Ticonderoga was a major blow to the British war effort, but the campaign also brought about the disillusionment of the Iroquois Confederacy, and saw the founding of the infamous Butler's Rangers and the first major campaign of Sir John Johnson's King's Royal Regiment.