As one of Upper Canada's largest flour mills, Welland Mills is an excellent example of the province's early milling technology.

Jacob Keefer embarked on building Welland Mills in 1846 and finished in 1847. He appears to have supervised the construction, hired craftsmen, millers and coopers and handled all financial matters. The Mill was operational in April 1847. Between the years of 1848 and 1893 there were continuous changes, while the reputation of the Mill grew impressively despite a devastating "Corn Law" Bill. The Exterior of the building is of bold coursed stonework.

Other outstanding features include: Gable roofs, simple cornices, sloped eaves. With three full floors and capacious roof space, Welland Mills is still a dominant landmark. Prominent owners have also added historically significant contributions to the eventful past of Welland Mills.

This building was designated under the Ontario Heritage Act as historically and architecturally significant.