The purpose of this study is to place the life and career of one man, John Graves Simcoe, into the context of Anglo-American frontier diplomacy in the 1790's. The American Old Northwest, with its Indian wars, foreign intrigues, and contests for hegemony was a volatile medium and it was quite often as necessary for the men making the decisions at the local level to resolve these thorny problems as it was for the diplomatists in Philadelphia and London. Simcoe was such an individual who, as Lieutenant-Governor of the newly created British province of Upper Canada, had the potential to make some impact on transatlantic diplomacy. An analysis of why and how he acted upon that potential is the main thrust of this dissertation.In order to answer the why, a complete study of Simcoe's background and experiences, particularly as a commander of Loyalist troops in the American Revolution, was necessary. A thorough search through his writings contained in manuscript collections in the United States, the United Kingdom, and Canada as well as his wartime journal has brought to the surface a great many clues to his attitudes toward the United States and the value of British social and political institutions. Continued research of the later writings of not only Simcoe, but of his contemporaries in Britain and North America has yielded an answer to the how. Of necessity, the scope of this phase of the work has been extended to include an analysis of the role played by the frontier Indians in the years leading up to the signing of Jay's Treaty.A modern study of all facets of Simcoe's career, especially those which have to do with the shaping of the domestic policies of Canada, is long overdue. Recognizing that need, yet wishing to focus attention on foreign affairs, the present work deals only with those points at which his administration of Upper Canada touched on AngloAmerican diplomacy.The results of the study indicate that Simcoe actually made very little impact on the history of this era, primarily because of his own ambition, his lack of any great civil, diplomatic, or even military talent, and above all, his total inability to focus his boundless energy on one scheme at a time. For all his stated opinion on foreign and domestic policy, Simcoe actually viewed everything from a quite narrow perspective and his consideration of every plan always suffered from his own egotism.Despite all of his attempts at greatness, Simcoe was a failure, not because of any lack of opportunity, but because of the defects in his own character and those cataclysmic pressures opposing him over which he had no control. The conclusion of this thesis is that no one with his qualities could have been effective and in many ways this was most fortunate. Another, more forceful man, given the same opportunities might well have been a great impediment to Anglo-American rapprochement in the 1790's.