Sir John Alexander Macdonald 1815-1891
First elected from Kingston to the Legislative Assembly of the Province of Canada in 1844, he was for forty-seven years a leading figure in the public life of his country. One of the Fathers of Confederation, he became the first prime minister of Canada and held the office 1867-73; 1878-91. Under his leadership the new Dominion was extended from sea to sea by incorporation of the territories of the Hudson's Bay Company, British Columbia and Prince Edward Island, and linked together by construction of the Intercolonial and Canadian Pacific Railways.
Plaque via Alan L. Brown's site Ontario Plaques. Full page here.