The property that surrounds Belhurst Castle was originally the site of a Seneca Indian village and home to the Council of the Six nations of Iroquois. In the early 18th century, the land became part of the state of Massachusetts and was purchased by two 18th century land developers in the spring of 1738. The land was again sold to a group of businessmen in 1810. These men built and operated Ontario Glass Manufacturing Company, the first glass company west of Albany. In May of 1824, the land was divided among the stockholders of the Ontario Glass Manufacturing Company, and William DeLong received the largest and most desirable portion of land, which is the area that is now home to Belhurst Castle.
