Fort St . Joseph ( Ontario ) Fort St . Joseph is a former British outpost on the southernmost point of St . Joseph Island in Ontario , Canada , on Lake Huron . The fort consisted of a blockhouse , powder magazine , bakery building , Indian council house and storehouse surrounded by a palisade . Situated on approximately 325 hectares along the St . Mary ' s River , Fort St . Joseph was the staging ground for the initial attack in the War of 1812 . The fort was not only an important military outpost , but also a significant meeting place for trade and commerce in the region . During its short but illustrious occupation , it was the British Empire ' s most westerly outpost . Today , Fort St . Joseph is operated by Parks Canada and is designated a National Historic Site of Canada . History . In 1783 , the Treaty of Paris was signed and the newly formed United States was awarded Michilimackinac , a trading post on Mackinac Island where Lakes Huron and Michigan connect . The strategic position of Michilimackinac gave the Americans sound control of the upper Great Lakes . Forced into making an urgent decision , Lord Dorchester , then Military Governor of Canada , advised that St . Joseph Island be occupied quickly , fearing that the Americans might lay claim to the island . Lord Dorchester had hoped to compete with and possibly replace Michilimackinac as the hub of the fur trade in the region while keeping Aboriginal allegiance . In the summer of 1796 , construction of Fort St . Joseph began . Since the arrival of British soldiers and engineers was so sudden , the Aboriginals became confused and stirred . However , the British treated the Aboriginals kindly , and they were content to trade with the soldiers . Strained relations between British and Americans became evident in 1807 because of the foreign and trade policies of the two countries . Control over the Great Lakes and fur trade was also a factor in these strained relations . Fort St . Joseph , as yet unfinished , was undermanned and contained out of date weapons so it was exceedingly apparent that Fort St . Joseph would be unequipped and incapable in defending itself amid attack . The Congress of United States declared war on Great Britain on 18 June 1812 . Appreciating the significance of Fort St . Joseph , Major - General Sir Isaac Brock , military commander of Upper Canada , sent a message to Captain Charles Roberts , commander of Fort St . Joseph ordering to prepare for immediate attack on Michilimackinac . On 16 July 1812 , Captain Roberts and an army of British soldiers , French Canadian voyageurs ( most of them from nearby Sault Ste . Marie ) , and about four hundred Ottawa , Ojibwa , Menominee , and Winnebago warriors set off on an unexceptional flotilla towards Fort Michilimackinac , arriving on the morning 17 July 1812 . Lieutenant Porter Hanks , commander of Fort Michilimackinac , was unprepared for an attack and Fort Michilimackinac was severely under - manned . However , before Lieutenant Hanks ' men could even spring to action , Captain Roberts ’ s army had already taken position and Hanks had no choice but to surrender . Meanwhile , Americans from Detroit arrived at Fort St . Joseph to find it deserted and they burned the fort and the North West Company storehouses that were present there . Until the end of the war , it was indisputable that Michilimackinac was British , but when the peace treaty was signed in December 1814 , Michilimackinac was restored to the Americans and the British decided not to rebuild Fort St . Joseph . The British then built a fort on Drummond Island between St . Joseph and Mackinaw however maintained the use of the powder magazine at the otherwise abandoned Fort St . Joseph . Fort St . Joseph was then forgotten when the British moved the garrison to Penetanguishine after the decline of the fur trade . Today . Until the early 1920s , no one had undertaken a serious interest in the forgotten fort . At that time , the Sault Ste . Marie Historical Society began to explore the ruins . It wasn ' t until shortly after World War II that a road was built to the site and a small picnic area established . The University of Toronto showed interest in the site in the late 1950s , and teams began archaeological digs in the summers of 1963 and 1964 . It was not until 1974 that Parks Canada assumed control of the site and a visitor centre was built . Today , archaeological digs continue and many new artifacts are discovered with each new excavation . The park attracts hundreds of visitors annually and is surrounded by natural beauty . Affiliations . The Museum is affiliated with : CMA , CHIN , and Virtual Museum of Canada .