Situated on Lake Ontario at the mouth of the Niagara River, Fort Niagara protected the portage around Niagara Falls, the principal route from Canada to the upper Great Lakes.  The portage was also the chief communication between Canada and the French colony of Louisiana and the point through which supplies and reinforcements could be moved to the Ohio Valley, where the French and their Native American allies were resisting British moves from Pennsylvania.  Although Fort Duquesne (Pittsburgh) had fallen to the British late in 1758, the French hoped to recover the post during 1759 and were massing troops to do so.  The capture of Niagara would sever communications between Canada and the West and forestall a French counterattack against the new British fort at Pittsburgh.

The route to Niagara from Schenectady led through the country of the Six Nations of the Iroquois, a powerful Native American confederation that had remained officially neutral in the conflict.  Late in 1758, however, the Iroquois declared their support for the British and pledged to follow Indian superintendent Sir William Johnson against the French at Niagara.  Their active participation made the expedition possible.

[Oneida Lake to the Mohawk River]. Pen and ink on paper, [1759]. Thomas Gage Papers. Map Division, Small Maps 1759.

Even with the cooperation of the Six Nations, an attempt on Niagara presented serious logistical challenges.  Five thousand soldiers and one thousand Iroquois warriors, with their supplies, provisions, and munitions had to be moved across New York to Oswego.  The most formidable obstacle on the route was the “Great Carry” (at modern Rome, N.Y.) from the upper Mohawk River to Wood Creek, which flows into Oneida Lake and ultimately Lake Ontario.  This portage was protected by Fort Stanwix and smaller guard posts.  North is at the bottom of the map.

A South View of Oswego on Lake Ontario in North America. Engraved for the London Magazine. London, May 1760. Map Division, Small Maps 1760.

The French had destroyed the British forts at Oswego in 1756.  Brigadier Prideaux’s army established a new fortification as a base for thrusts against Niagara and Montréal.  This view of Oswego from the south depicts the post destroyed in 1756.  The 1759 fort was constructed on the high right bank.

Charles Rivez, “Plan of Fort Ontario Built at Oswego in 1759.” Detail. Pen and ink on paper, [1759]. Thomas Gage Papers. Map Division, Maps 4-L-12.

The British began construction of a new and much stronger Fort Ontario soon after arriving at Oswego.  Like Fort Pitt and Crown Point, both also begun in 1759, it was pentagonal in shape with five bastions.  Fort Ontario was designed to resist artillery and to bar the French from the Iroquois country.

George Demler, “A Sketch of the South Shore; of Lake Ontario Between Oswego; and Niagara, and from thence up the River, To a Boute Two Miles a Bove the Falls.” Pen and ink with watercolor on paper, 1759. Thomas Gage Papers. Map Division, Maps 4-L-11.

At Oswego, Brigadier Prideaux divided his army and set out in bateaux for Niagara on July 1 with 2,500 British and provincial troops, 1,000 Iroquois warriors, and a small train of siege artillery.  Their westward route followed 150 miles of Lake Ontario shoreline.  Ensign George Demler mapped the coast from Oswego to the Niagara River.  North is at bottom.