Many historic references to Fort Oswego actually refer to other forts that existed simultaneously or later. The terrain at the site explains this. The original fort was built around the trading post on the lower ground on the north west side of the mouth of the Oswego River. This was convenient to canoe and bateaux traffic. A stone blockhouse was added in 1727, and was called Fort Burnet. A triangular stone wall, ten feet (3 m) high and three feet (1 m) wide was added in 1741, and the entire enclosure was called Fort Pepperrell (a marker can be found designating the area of Fort Oswego on the north west side of the river along a sidewalk). Besides these expansions, Fort Ontario was started in 1755 as a palisade on the high ground on the north east side of the river, and Fort George was add