Port Arthur
On Thunder Bay just north of Fort William, engineer Simon Dawson established the eastern terminus of the Canadian government's proposed land and water route connecting Lake Superior and the Red River, for which construction began in 1869. The next year, when Colonel Garnet Wolseley led the Canadian Expeditionary Force over the Dawson Road to quell the Red River Resistance, he named his camp here Prince Arthur's Landing. It was renamed Port Arthur and chosen as the site of the Canadian Pacific Railway's first grain elevator in 1883, and then it became a central terminus of the Canadian Northern Railway in 1902.
Plaque via Alan L. Brown's site Ontario Plaques. Full page here. Also submitted by @willjpratt