Niagara Land Purchases
To obtain land on which to settle Loyalists and dispossessed members of the Six Nations of the Iroquois, Guy Johnson in May 1781 and John Butler in May 1784 negotiated treaties with representatives of the Mississauga and Chippewa of this region. The Crown thereby acquired title to a tract of land 6.4 km wide along the west bank of the Niagara River between Lakes Erie and Ontario. These two cessions were later confirmed by a third treaty negotiated by John Graves Simcoe, Lieutenant-Governor of Upper Canada, and certain Mississauga chiefs at Navy Hall in December 1792.
Plaque via Alan L. Brown's site Ontario Plaques. Full page here.