Laurier House Home of Two Prime Ministers of Canada
Erected in 1878, this house was purchased in 1897 by the Right Honourable Sir Wilfrid Laurier who occupied it until his death in 1919. Later it was bequeathed by Lady Laurier to the Right Honourable William Lyon Mackenzie King, whose residence it was from 1923 to 1950. He in turn bequeathed it to the nation.
Plaque via Alan L. Brown's site Ontario Plaques. Full page here.