<P> Twelve years after the British defeated the French, the American Revolutionary War broke out in Britain's lower thirteen colonies . Many Québécois would take part in the war, including Major Clément Gosselin and Admiral Louis - Philippe de Vaudreuil . After the British surrender at Yorktown in 1781, the Treaty of Versailles gave all former British claims in New France below the Great Lakes into the possession of the nascent United States . A Franco - Spanish alliance treaty returned Louisiana to France in 1801, but French leader Napoleon Bonaparte sold it to the United States in the Louisiana Purchase in 1803, ending French colonial efforts in North America . </P> <P> The portions of the former New France that remained under British rule were administered as Upper Canada and Lower Canada, 1791--1841, and then those regions were merged as the Province of Canada during 1841--1867, when the passage of the British North America Act of 1867 instituted home rule for most of British North America and established French - speaking Quebec (the former Lower Canada) as one of the original provinces of the Dominion of Canada . The former French colony of Acadia was first designated the Colony of Nova Scotia but shortly thereafter the Colony of New Brunswick, which then included Prince Edward Island, was split off from it . </P> <P> In Canada, institutional bilingualism and strong Francophone identities are arguably the most enduring legacy of New France . </P> <P> The only remnant of the former colonial territory of New France that remains under French control to this day is the French overseas collectivity of Saint Pierre and Miquelon (French: Collectivité territoriale de Saint - Pierre - et - Miquelon), consisting of a group of small islands 25 kilometres (16 mi) off the coast of Newfoundland, Canada . </P>

Why was keeping the colony of new france so important to france