Ermatinger House
This house, built between 1814 and 1823 by Charles Ermatinger of the North West Company, is the oldest surviving house in northwestern Ontario. Constructed when Sault Ste. Marie was still a small fur trading post on the Upper Lakes, this fine house soon became the centre of the district's business and social life, and was noted by such visitors as Lord Selkirk, Anna Jameson, Sir John Richardson, Paul Kane and George Catlin.
Plaque via Alan L. Brown's site Ontario Plaques. Full page here.