Battle of Fort Oswego (1756) - Background

Background

Following the beginning of open conflict between French and British colonists in 1754 with the Battle of Jumonville Glen, the governments of Britain and France both sent regular army troops to North America to further contest the disputed territories of the Ohio Country and other border areas, including the frontier between the French province of Canada and the British province of New York, an area in present-day Upstate New York that was then largely controlled by the Iroquois nations. Part of the British plans for 1755 included an expedition to take Fort Niagara at the western end of Lake Ontario. The planned route for this expedition followed the Oswego River to the lake, with a major base of operations at the mouth of the river (where the present-day city of Oswego, New York is located). Under the direction of William Shirley, the governor of the Province of Massachusetts Bay, the original Fort Oswego was reinforced, and two additional forts, Fort George and Fort Ontario, were built in 1755. The planned expedition to Fort Niagara never took place due to logistical difficulties, and the fortifications around Oswego were manned during the winter of 1755–56.

The French in 1755 had the only large naval vessels on Lake Ontario, and moved freely about the lake, between Fort Niagara in the west and Fort Frontenac at the head of the Saint Lawrence River. In March 1756 they launched a winter attack on Fort Bull on Wood Creek. Fort Bull was a key depot on the supply line for the Oswego forts, which was the waterway leading up the Mohawk River and crossing over to the Oswego River watershed. In the successful attack, they destroyed many provisions intended for the Oswego garrison, and effectively ruined Shirley's plan to attempt the expedition against Fort Niagara in 1756. Following orders of the Governor of New France, Pierre François de Rigaud, Marquis de Vaudreuil-Cavagnal, in May 1756 French and Indian raiding parties under the command of Louis Coulon de Villiers began harassing the Oswego garrison from a camp on Henderson Bay (south of present-day Sackett's Harbor, New York).

General Louis-Joseph de Montcalm arrived in Montreal in May 1756 to lead the French army troops. He and Governor Vaudreuil took an immediate dislike to one another, and disagreed over issues of command. Concerned over the massing of British troops at the southern end of Lake George, Montcalm first went to Fort Carillon on Lake Champlain to see to its defenses. Vaudreuil meanwhile began massing troops at Fort Frontenac for a potential assault on Oswego. Following favorable reports from the raiding parties, Montcalm and Vaudreuil decided to make the attempt.

Governor Shirley received word in March 1756 that he was to be replaced by John Campbell, 4th Earl of Loudoun. Loudoun's second in command, General James Abercrombie, only arrived in Albany in late June, and Shirley spent the intervening time shoring up the supply line to Oswego in anticipation of leading an expedition against the French forts on Lake Ontario. In June William Johnson traveled to the Iroquois headquarters at Onondaga, and successfully negotiated support for the British side with the Iroquois, Shawnee, and Delaware, forces that Shirley also hoped to use for his expedition. Shirley also hired 2,000 armed "battoemen", men experienced in sailing and shipbuilding. Under the command of John Bradstreet, these men successfully resupplied the forts at Oswego in July, although they were attacked by a French raiding party on their way back, suffering 60 to 70 casualties.

When Loudoun arrived in Albany in late July, he immediately cancelled Shirley's plans for an Oswego-based expedition.