The First Sault Ste. Marie Canal
The French explorers who first reached this favoured Ojibway hunting and fishing ground were soon followed by fur traders and missionaries who built a post and mission. By 1762 the region had come under British control and the trade eventually fell into the hands of the North West Company. Canoes and larger boats were towed through the rapids, sometimes by oxen, until 1797-8 when the Company built a canal with a wooden lock sufficiently large to admit a Montreal canoe. The lock was destroyed by American troops in 1814.
Plaque via Alan L. Brown's site Ontario Plaques. Full page here.