In the Beginning
For several thousand years, long before the white man had ever arrive to the area of the present day city of Oswego, the land was the property and home to the Iroquois Indians “Six Nations” The Mohawk, Onondaga, Huron, Seneca, Oneida and Cayuga.
Oswego, situated on the mouth of the Oswego river and on the southeastern shores of Lake Ontario was first recorded being discovered by white men in “1654” by French Jesuits, who established missions for the purpose of the conversion of the Iroquois. The French had previously explored the St. Lawrence; and in 1615 Champlain, in an expedition against the Onondagas, passed through the Eastern part of the county. In 1700 the English explored the country occupied by the Five Nations as far west as Oswego, and in 1722 a trading house was built there under the direction of the New York colonial government. From that period considerable trade was carried on by the English between Oswego and Albany through the Oswego River, Oneida River, Oneida Lake, Wood Creek, and the Mohawk river valley. In 1727 the English built a fort on the West bank of the Oswego river, near its mouth.
The French, claiming this whole territory, demonstrated against the action of the English, and several times planned expeditions to destroy the fortifications, but did not carry them into effect. Upon the commencement of the “Old French War” of 1753, Fort Ontario was erected on the East bank of the river; and another fort was built upon the summit of the west ridge in 1755.4 In the summer of 1756, a total of 5,000 French and Indians under Montcalm, with a heavy train of artillery, consisting of 30 guns of large caliber, crossed the lake from Fort Frontenac (now Kingston) and appeared before this place. The forts were attacked Aug 11, after 3 days’ of hard fighting, the three forts surrendered on the 14th of August to thee French General Montcalm and and his overpowering forces.
The French victors then demolished the forts and the English vessels and then retired.
In 1758, English Col. BRADSTREET, with 3,350 men, crossed the lake from Oswego where they demolished and reduced Fort Frontenac {now Kingston}. After destroying the fortifications and securing the military stores and vessels, Col. Radstreet and his forces returned to Oswego and rebuilt the forts there. Fort Ontario was greatly enlarged, and built in the most substantial manner however Fort George and Fort Oswego were never restored.
In the summer of 1760, the powerful army of Lord Amherst {pictured here} embarked here on an expedition down the St. Lawrence. From this time Oswego became the most important military station upon the western frontier. During the Revolution, it was strongly garrisoned, and formed the headquarters of many of the marauding parties that desolated the frontier settlements. It continued in the possession of the British until 1796, when it was surrendered under the provisions of Jay’s treaty. https://history.state.gov/milestones/1784-1800/jay-treaty